Hellcannon
The Hellcannon is quite a special unit, combining elements of a stone thrower with a monster. First of all, it follows the rules for Monster Handlers and is a serious fighter with WS4 S5 T6 W5 A5 AP-1 Armour Bane (1), Armour Save 4+, Regeneration (6+) (with Warp-Spawned) and Impact Hits (D6). Curiously it does not have any Stomp Attacks. It is also Unbreakable, Immune to Psychology and causes Terror. As if that were not enough, you can fire a mighty stone thrower with the 3" template and S5 AP-2 Armour Bane (1) - S10 AP-5 under the central hole! - and even one casualty causes a panic test. Even more, arguably all hits cause Multiple Wounds (D3), not just the one under the central hole!
All this power comes at a (small) price, and at the start of your turn you need to pass a LD test or roll on the misfire table. Luckily the Chaos Dwarf handlers have LD9.
Remember that a Hellcannon is not a war machine so it does not benefit from your sorcerers’ Infernal Engineer special rule.