When I wrote about toads, I understood that many wouldn't appreciate it, but I still believe that a swamp without toads is just a swamp, perhaps one belonging to some industrial factory.
Level 3: Swamp Snake.
Snakes are very cunning, and therefore it is beneficial to use them in battle.

attack-------5
defense-----1
damage--------3-4
HP----------16
speed----6
initiative-10
growth-----8


Added 2 minutes later
Improved - poisonous swamp snake.
And poisonous snakes are even more cunning, so it is even more beneficial to use them in battle.

attack-------7
defense-----1
damage--------4-5
HP----------18
speed----8
initiative-12
growth-----8

Abilities: poisons.