I hope it's not too late, but I have a tower. It's called the Vortex Tower. It is a sorcerer's tower, but for flying mobs. It can attack land mobs, but is twice as effective against the flying mobs. The animals are bats. It starts with 2 bats, but gains 1 per upgrade. Same other stats as the sorcerer's tower, except it is a 4 by 4.