The Doomhauler at work on Dooq.
The Doomhauler is a type of Irken military vessel. It is first introduced in Issue 25 of the Invader Zim comic series.
Summary[]
From what is seen, the Doomhauler appears to be a type of troop transport, as when it is shown in flashbacks to Planet Dooq, it can be seen disgorging troops and land-based military vehicles. It also appears to serve as a command base, as implied by its central position in the Irken forces' landing site and by Commander Poki first assigning orders for the mission while still aboard it.
The Doomhauler shown on the mission to Dooq is so far the only one to appear in the series, and is destroyed by the explosion of gigabombs which Zim sets off while trying to distract local forces. Years later, Fitzoo-Menga raids the wreckage of the Doomhauler for a neurothing to use to forcibly remove Zim's PAK as part of his plan to steal Zim's body, and shortly after, Zim and Fitzoo-Menga's fight ends on top of the wreck.
It is unknown how common Doomhaulers are in the Irken military.