Ultralisk

Ultralisk is ths strongest unit in Starcraft. The enormous Ultralisk is the crown of Zerg evolution. If you produce many Ultralisks, your enemy's units aren't able to live. With their ability to withstand immense firepower, the Ultralisks are best used as damage absorbers. Keep the Ultralisks in the front line whenever possible so that they can deal their damage while facing the brunt of the enemy's attack.
But this glamorous unit has a few week points. First, Ultralisk requires a expensive price to produce it. So if you want to make them in a large group, you should secure ample minerals and gases. Next one is Ultralisk hasn't air attack ability. If you don't want to lose your Ultralisk from enemy's air units, prepare some support units. And the last one is their slow movement. But you can upgrade Ultralisk's speed. This upgrade is very useful, so you must do that if you want to use Ultralisks.