So it's the middle of winter, and there's this old woman, and she sees a snake, huddled up miserable and half-dead in the snow.

Snake says "Please pick me up and keep me somewhere warm."

And the old woman says "If I picked you up you'd bite me and I'd be poisoned."

So the snake says "Yeah, that sounds like something I'd do. But, if you don't, I'll die. Rescue plz?"

The old woman dithers and worries until the snake turns blue and passes out. Then she takes pity on the poor snake, picks it up and tucks it into her cleavage, and continues with whatever ridiculous errand had her out tromping through the snow. Buying eggs or something. I don't know.

After she gets back home and sits by the fire, the snake thaws out, wakes up, bites her right on the boob and injects some poison. Not very much, since it was weak and hungry and making that stuff is metabolically intensive.

She says "Ow! What was that for?"

Snake says "I'm a snake, it's what I do. Everybody knows that. Why'd you go and stick me in such a... oh, hey, free milk."

And they lived happily ever after.

The end.