Imagine a hamster in a hamster wheel. Now imagine that the hamster wheel is ten meters tall, fires nuclear-magic-laser beams that are powered by solidified hell energy, has a drugged-up ratman engineer with a gun on top and instead of a hamster it houses a pack of giant mutant rats hopped up on drugs and steroids (who are likely on fire and cannibalizing each other while running). That is the DOOMWHEEL. DOOMWHEEL is always written in all caps and is one of the only things in Warhammer Fantasy that's XTREME and METAL enough for Doomrider to look at. But who cares what Doomrider says, since it invariably loops back to cocaine, LSD, and whores.
DOOMWHEELS are insanely popular among neckbeards. They are also notoriously unpopular among GeeDubs staff, and they axed them from the Skaven list. We made them regret that, and now DOOMWHEELS ARE COMING BACK. DOOMWHEELS ARE BACK. FUCK YEAH!
Lore of the DOOMWHEELS
The DOOMWHEEL is Clan Skryre's crowning achievement, and the very greatest work of that absolute madrat Ikit Claw, who was obsessed with outdoing himself on pretty much every weapon he'd had a hand in developing up to that point. The DOOMWHEEL is the result of that obsession; a terrifying design so openly and unabashedly "Skaven" that even the imperial college of engineers look at this mechanical monstrosity and scratch their heads at the thought of how the hell these things even manage to stay upright without exploding immediately. The team of rats inside the wheel both power the guns by charging the warpstone generator, and also keep the thing moving, while the drugged out Warlock-Engineer directs the DOOMWHEEL forward, blasting warp-lightning until it runs out of things to shoot. Part of it's genius is the sheer audacity of it: most don't know what the hell the Skaven are doing when they first see it, and are often caught very off-guard by the team of mutant ratmen getting into this overturned barrel of warpstone. They are usually then completely smashed flat or zapped into dust by said warpstone barrel moving faster than most cavalry charges.
That said, as engineeringly and aesthetically perfect as they are, they do have at least a few downsides. Inevitably the rats rolling around in the wheel itself eventually get exhausted or begin to pass out from inhaling warp fumes, and the DOOMWHEEL slows to a crawl, and a stationary DOOMWHEEL is a near-dead one; as it can't recharge after it fires it's blasts of warp-lightning, and more importantly, can't run over any man-things that might be interested in it's immediate and total destruction. The Dwarfs, having long been victims of the DOOMWHEEL, have a suitably grimdark strategy of sacrificing their own cannon crews to get these things are slowed down enough that their artillery can hopefully blast them apart in a suitably wild explosion.
Tactically, they are the Skaven's ultimate linebreaking behemoth, designed to just run over anyone or anything that happens to be in the Warlock-Engineer's very addled vision, and cause absolute havoc. They're good for just about that and that alone, but it's saying something that even after the world got butt-fucked and then rebooted, DOOMWHEELS didn't even change much, because they didn't have to.
Total War WARHAMMER 2
How many DOOMWHEELS?
Not Enough DOOMWHEELS!
NEVER ENOUGH DOOMWHEEELS!
YES YES DOOMWHEEL ARE BACK BACK, KILL THOSE MAN-THING - DWARF-THING BECAUSE THEY ALL DIE DIE!!!!
An Ode to DOOMWHEEL
To be sung to the tune of the Theme Song to Team America.
Oh, Skaven Doomwheeels...
The great Doomwheels...
GO, DOOMWHEELS! FUCK YEAH!
ROLLIN' ALONG TO SAVE THE MOTHERFUCKING DAY, YEAH!
GO, DOOMWHEELS! FUCK YEAH!
NOW IT'S ROLLING TOWARDS OUR LINE, YEAH!
IMPERIALIST, YOUR DAYS ARE AT AN END!
SCORCHED, RAMMED, FLATT'NED, TO MORR SEND!
GO, DOOMWHEEL! FUCK YEAH!
Cue Warp-guitar solo.