I saw there is already a suggestion for a Hydra, but here is my version of it.

DE troop. Giant snake with one head per level. Attacks multiple targets at the same time, one with each head.
Drops a head when it's loosing health, a 3 headed hydra drop a head every 33% health.
Regens health, heads grow back when health gets back. Ranged attack, high health.

Level 1:
1 Head
1 Target

Level 2:
2 Heads
2 Targets

Level 3:
3 Heads
3 Targets