Shoreline shark

Waves lapped at the shore of an otherwise silent rocky beach, the odd crab or seagull being the only living things nearby. Above the surface, at least, as the only person currently at the beach was below the water; a nervous anthropomorphic thresher shark, fidgeting his long tail with his webbed hands and looking up at the surface. He wanted to explore above it, but he knew that whatever was up there instead of water was something he couldn't breathe. He'd tried before; inhaling it made his gills feel as if they were being torn at. This time, he had an idea, and was gathering up the courage to try it.
Eventually, the shark took a deep breath, closing his gills and puffing his cheeks, and swam up to raise his head above the water. It felt fine this time, if a bit strange, a current of some kind rubbing along his head. While his eyes struggled to adjust to the different medium, he could see a rocky, bumpy landscape that reminded him of some parts of the seafloor he'd seen.
Diving under again, the now more confident shark exhaled to breathe normally again, and swam along the seabed to get closer to the shore. The water grew more and more shallow, until even crawling along the bottom would leave his dorsal fin and the top of his head above the surface. Breathing heavily to prepare himself, water quickly passed through his gills, until he took another gasp and held in what water it had gotten, and tried to stand up.
Water poured off the thresher's body and his legs quivered as more of him than ever before left the sea. He wasn't used to supporting his full weight, and even underwater it was rare that he'd bother to walk instead of swimming, his flipper-like feet making it rather difficult. Awkwardly, he began to slowly walk forward, raising each foot a fair bit higher than necessary as he wasn't really sure what he was doing. The water quickly became even more shallow, only going up to his ankles, than his toes, and finally nothing at all as the shark entirely left the water for the first time, holding onto his tail so it wouldn't drag on the ground.
This was certainly a strange place; the ground seemed to be entirely made of rock, with several small pools of water strewn about, some of which looked like they'd be big enough for the shark to breathe from. Off in the distance, opposite the water, the ground turned green, though he couldn't make out any more detail from so far away, and a few strange plants he didn't recognize were near him. He wandered for some time, but his legs quickly grew tired, and one fumbled step caused him to trip, spitting up some water from the impact of hitting the ground. Covering his mouth for a moment, the shark decided to just stay on his hands and knees for now so he could more easily support himself. He couldn't hold his tail like this, so he did his best to keep it off the ground with its own muscle, though it was only barely enough and would still momentarily drag every now and then.
The thresher's gills were getting pretty uncomfortable, and he decided it was time to get a breath, crawling over to a nearby tidepool and dunking his head in it. There wasn't a whole lot of water to breathe, but there was enough for him to catch his breath. With another gasp, he raised his head again to continue his exploration. At this point having been on land for about 5 minutes, most of his body was beginning to itch as it dried out. Even with the tidepools for the shark to breathe from, he was going to need to return to the ocean at some point to get wet again.
After another couple minutes, he found a strange object floating in one of the tidepools, and picked it up to get a somewhat better look at it. It was cylindrical, made of a transparent material he didn't recognize, and seemed to be a container as it had a small opening extending from one end, although all it had at the moment was a bit of water. The sight of that water sloshing about did give the shark an idea of how he could use this, though, and he submerged the container in the tidepool it had been in.
Bubbles floated to the surface for a few seconds, and when they stopped, he pulled the container back out, which was now full of water. This was going to be a big help! First, he poured the water out over his head, letting it flow down his body and relieve the itchy dryness that had been building up, then refilled the container and tried breathing from it by pouring the water into his mouth. That worked as well, although he had to exhale some of what he'd been holding to make room for it, the used water splattering on the ground.
With another filling of the container, the shark now felt that he'd be able to safely go farther inland, though he had to be careful not to spill much water as he had no way of closing the container. As he came closer to the green part of the ground, it finally came into focus, and he could see it was a field of small green spikes! While it didn't seem like he could go any farther, the shark poked at one of the spikes just to be sure, and it turned out he could effortlessly bend them, even from their top. These strange spikes were entirely harmless, and he crawled onto them to no ill effect.
Some distance into the field of spikes, he started feeling the need to breathe. With only one breath's worth of water held in the container, though, he had to make it count, and would continue to hold his breath for now. A while longer, and the shark found yet another strange thing; a dark brown pillar that extended far above him, with more green things near what appeared to be the top of it. Whatever it was made of was hard and rough, and had an abundance of much smaller pillars branching off of it, sort of like coral.
A few similar small pillars were at the base of this one, and one in particular was as long as the shark was tall. He picked it up to inspect it, then gave a shot at propping himself up with it, setting the water container aside for the moment. This pillar was pretty sturdy, and seemed like it would enable him to stand up without getting exhausted like before. After a brief test of walking with it, he covered his mouth again, remembering he needed to breathe, blushing from strain. Grabbing the container again, he poured its water into his mouth to refresh his breath, letting out the water he'd been holding onto.
With the container empty save for a few useless drops, the shark grabbed their new walking stick and started back to the shore. It went quite a bit faster this time, and he was only barely feeling any need for water when he got there! Another round of soaking, refilling and breathing, and he went back to the spike field to just relax for a while, sitting down. This weird environment was growing on him, he'd definitely be coming back with better equipment to explore more easily. Even the thought of being this far away from a water source was strangely appealing...
His twin claspers were beginning to harden as he thought about the threat of choking on whatever this substance around him was. With some water being right by him in the container in his hand, what harm would there be in indulging himself for a while? He began stroking his claspers, alternating between each one every few seconds, before carefully setting the container next to him so he could use both hands. Even as he started needing to breathe, he didn't go for the water container, simply allowing his strain to slowly increase along with his pleasure. Blushing from both those things, he eventually grabbed his neck to keep any water from leaking out of his gills and awkwardly grabbed both claspers with his remaining hand.
Another minute or so, and the thresher was starting to lose the fight to hold his breath, water seeping from his lips and his blush turning purple... But, at last, he came, each of his twin rods spurting their first shot of cum at once before their timing became uneven, both shooting at slightly different rates. The shark carelessly moaned in pleasure, water pouring from his mouth, before inhaling. Instantly, he coughed heavily, the majority of his remaining water spraying out, and gripped his neck tighter while fumbling for the water container as he continued to cum. Panicking, he accidentally knocked the container over, a substantial amount of its water spilling out as it rolled away from him before he could scramble over and right it, gasping down what water remained in it.
His orgasm ending, the shark scrambled to his feet with the small pillar, not bothering to bring the empty container with him. The amount of water he'd managed to inhale hadn't done much, but he could at least hold his breath again as he made for the shore, awkwardly running with the pillar's support. There were bits of pain all over him as his body was almost entirely dried out, especially along his tail which he'd forgotten about raising to keep it off the ground. Already the shark felt he needed to cover his gills again, both sets of them feeling the same way he once did when he went too close to a geothermal vent deep in the ocean.
Eventually, his walking stick got stuck on something, the sudden interruption of his movement making him trip! He spat up water like last time, and his gills flared as he reflexively gasped, immediately going into a coughing fit. The feeling of heat in his gills quickly got even worse and he curled up on the ground for a moment, loudly choking on whatever this deadly substance was as his blush turned blue. Feeling around for his walking stick, he grabbed on and tried to pull himself up, before falling back down as he overshot its height. Except, he didn't; it had snapped during his fall!
Gathering what fading strength he had left, the thresher struggled to stand up on his own, legs shaking worse than before, before they buckled and gave out entirely, dropping him back to his hands and knees. Hoarsely gasping, he just crawled forward instead, shivering and starting to lose feeling in parts of himself. After about 30 seconds of desperate struggling, he was back on the rocky beach, but his body had had enough.
He collapsed onto his front, weakly panting and barely able to move. Where he'd landed, even with his blurry and dim vision, he could see a tidepool a few feet in front of him. With a huge effort, he dragged himself toward it, getting within inches of the life-saving water before he couldn't move the weight of his body any more. If he could just get his hand in there, and then get it on his gills, he could survive this disastrous exploration! Barely managing to even raise a hand, the shark reached for the water, and allowed his hand to simply fall in. But, he couldn't lift it again. His strength was entirely gone, and he simply lay still, touching what could save his life if only it got to his gills. The thresher stared at the water with lidded eyes that slowly grew unfocused, his suffocated and blue-tinted body drifting into unconsciousness, never to wake.