Let's come up with an amphibian race!

Regarding the crocodiles, let's say there's a 20% chance they'll attack. This will work if the number of crocodiles is equal to or greater than the number of units they're attacking, but not if it's less. Maybe that would work... Also, what will be the name of this unit? If it's "crocodile," it doesn't sound very good; it would be better to come up with something else.