Our next door neighbour decided that he was going to breed mice. Either as pets or as rodent feed, I can't remember. Then, for reasons he refused to elaborate, he let them all go. Hundreds and hundreds of little mousies, none of them with a wit of fear for the human species. To make matters worse his father had slaughtered the local carpet snake on the grounds that "The only good snake is a dead snake, hur hur hur!" Everyone on the block bought hundreds of traps. The neighbourhood cats because so bloated they refused to move. Our cat kept killing them- she was a vicious bitch- but she lost all interest in eating them, and guess who ended up having to scrape mouse foetus up from the veranda steps? After two weeks of holding out on poison for the sake of our cat and dog, we gave in and bought some ratsack. The unbelievable stink- you could smell it from three blocks down the street. The only reason our cat wasn't poisoned was that she was also an attention whore and refused to eat anything unless we congratulated her on her latest murder first. So we were able to just take the corpses away from her, which pissed her off but didn't stop her from showing us the next one. I don't know how the rest of the block's animals fared. Having lived through a human-made plague I'd hate to see a plague of wild mice. It'd be surely terrifying and even more difficult to get rid of.