Flood thrasher form
It takes the form of a large, hulking, tentacled creature with a slight resemblance to Earth-born primates, that attacks its opponents by ramming itself into the target and slashing with its powerful front limbs. The way the form was utilized by the Flood is similar to how the Flood tank form is employed, specifically as a powerful close-range attack unit. Despite their similarities, there are significant differences between the two forms.
The Thrasher form appears to be a creature converted to a combat form as opposed to being a pure form, with the original creature likely once indigenous to the outer hull of the Etran Harborage. This creature appeared to have a leathery grey skin, though the Flood conversion has caused this skin to be interspersed with Flood growths and tentacles.
Thrasher forms were present on the outer surface of the Etran Harborage in 2531, as part of the Flood infestation on the shield world. During the battle between the forces of the UNSC Spirit of Fire and Covenant, Thrashers would form a part of the Flood outbreak attacking both sides, in which they would target armoured vehicles such as M808B Scorpions. With the shield world's destruction, it is likely that all thrasher forms were destroyed. Thrasher forms have yet to be observed on any other installation.
Thrasher forms are a Flood unit in Halo Wars. They are the primary anti-vehicle unit available for the Flood, and are capable of doing great melee damage to tanks and other ground units.
List of appearances