Mutalisk (StarCraft II)

Overview
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 (except when spread out), phoenixes, and corruptors. The mutalisk is also countered by marines (especially those equipped with combat shields and stimpacks) and ghosts, due to their high damage against lightly-armored units.

Overall, mutalisks are more versatile than corruptors, due to their ability to raid, harass and decimate opponents without anti-air capabilities. Alternatively, the corruptor is strictly an anti-air unit.

Heart of the Swarm
In the campaign of Heart of the Swarm, mutalisks can mutate into either vipers or brood lords after completing the requisite evolution mission. Their visual appearance changes accordingly.

Co-op Missions
Mutalisks are available to Kerrigan and Abathur in Co-op Missions. Kerrigan is able to evolve her mutalisks into brood lords, while Abathur's evolve into guardians and devourers. Both require a greater spire to evolve their mutalisks.

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.

There has been some community concern about the effects of massed mutalisks against protoss. Blizzard considered whether a change is truly necessary in early 2012.

Heart of the Swarm
Mutalisks had two upgrade in the campaign that were cut. One, called "fibrous core," increased their maximum life by 35. The second, "interlocking scales," gave the mutalisk +1 armor