Mutalisk (StarCraft II)

Tactics
The mutalisk's attack is still able to strike multiple targets, bouncing to strike up to two additional targets as in StarCraft. The attack automatically bounces towards the next closest enemy.

Mutalisks are able to stack quite well but it is difficult for them to remain clumped. Mutalisks spread out when they move or attack. With some micromanagement, mutalisks are able to attack on the move as before.

Mutalisks are strong against vikings, brood lords, and void rays, and are weak against, thors, phoenixes, and corruptors. The mutalisk is also countered by marines (especially when equipped with combat shields and stimpacks) and ghosts, due to their high damage against lightly-armored units.

Development
Mutalisks lost the ability to morph into anti-ground flyers because the anti-air corruptor became "useless" once the zerg player had "swept the sky". The corruptor needed the morph more.