We can use Fooruman's ramming speed against Ice Hydra, then Shuriken's Ninja speed to inflict 23 damage in total, not counting the hydra's defence. This will kill the hydra over the course of 2 turns. On the other hand, we will do 3 damage and get hurt badly if Succubus heals Ice Hydra twice (in those two turns), but she will no longer be able to heal, provided 2xheal is all she has.