Ultraheavyweight
An Ultraheavyweight is a bot weighing more than 1200kg (SHW) but less then 5000kg. The weight class was invented by 123savethewhales.
Ultraheavyweights are rarely built, but there has been an UHW tournament, Clash of the Titans, made by Somebody.
Due to no special components done for the UHW class, they often tend to look like fortresses of metal than anything else, and going to the weight limit is often a difficult matter on it so efficiency starts to suffer as the builder gets annoyed and adds random components on his bot. They can also be very laggy and loading matches with even 2 UHW's can crash computers at times (unless the pause/break button is used before hitting start and loading the match, of course).
The ultimate UHW is Firebeetle's Hammer of Justice. HOJ, however, uses custom components and is way heavier than the limit of 5000kg.
Firebeetle has now come out with a new version of Hammer of Justice called Hammer of Judgement, which is very similar but smaller (to fit in more arenas) and with some extra added features.
Above 5000.0 kg is the Gigaheavyweight bot class.