Hot and Cold Dripping Rats
You approach the rat faucet, and note that rats are still dribbling out of it at a rate of one every six or eight seconds. If you wanted to fight a rat, this would be a convenient place to get one.
You hang around the rat faucet, waiting for a rat to drip out. If adventurers could get these pipes hooked up to their own campsites, you muse, they could level up at home without all that messy adventuring. There must be some sort of corporate interest preventing municipal high-speed rat access to home consumers.
Ah, here's your rat.
|Leave it alone|
You decide you've had enough rats for now. If you later decide you need one for some reason, you'll know where to find it.