Morkanaut
The Morkanaut is a large, heavily armed walker created by the Mekboyz and piloted by a particularly skilled, or deranged, Mek. Morkanauts make use of the most fantastical weapons and gizmos that their creators can devise. The Morkanaut's weapon options, depending on configuration, may include a pair of twin-linked big shootas, twin rokkit launchers, a skorcha, a suped-up power klaw, a kustom mega-blasta, a kustom mega-kannon, and a kustom force field.
For Maximum Lulz give the Morkanaut Extra Armour and Grot Riggers. Then buy a Big Mek and pay for Da Fixer Uppers. Don't forget to include the kustom force field option. This build runs around 360pts minimum, but the 'Naut will absolutely refuse to die thanks to a 5+ Invulnerable save against shooting, It Will Not Die, ignoring Crew Stunned & Shaken results and the ability to fix either Weapon Destroyed, Immobilized, or Hull Points on the roll of a 3+. Or you can do a discount version of the above by using Burna boys with maximum meks, or even the slotless meks each HQ choice unlocks.
Being much larger than a Deff Dred, the Morkanut is essentially a small Stompa. Its size therefore allows it to carry up to half a dozen passengers in its armored belly, heaving them out to begin the slaughter on their own before getting back to fragging shit. The Morkanaut's brother is, of course, the Gorkanaut.