As everyone loves rats, here some more 'rats'.
Ok, they're probably not the best thought out cards, but maybe we can turn this into a rats thread. Add your own, refine and mock.
All cars have 20 copies.
Locust:
Cost: 3$
+1 Card +1 Action
Gain a Locust. Trash a card from you hand other than a locust. Each other player either gains a locust or draws 3 cards, trashes 2 and discards the other. When you trash this return it to the supply and every player gains a locust.
Baby Snakes
6$
+1 Card +1 Action +2$
Gain 2 baby snakes. Each other player reveals the top cards of their deck. If eithr are a Baby Snakes they reveal their hand and trash all cards other than victory cards, otherwise discard.
Mole
2$
+1 Action
Gain 2 moles. Reveal your hand, if you have no victory cards in it and this is the first action card you've played this turn then +4$
Maggots
0$
If this is the first time this game a Maggots has been played, each other player gains a maggots. When you trash this, gain 4 maggots.
Piranha
3$
+1 card +1 Action +3$
Gain a Piranha. Each other player draws 2 cards and reveals their hand. Any player with two or more piranhas trashes all cards in their hand other than piranhas.