I was thinking more along the lines of, at the beginning of each turn roll a D6, if it's a 1 then look at "summin's gone wrong boss".
1-2 = "Oh zog!" Boom big template, strength 5 hits to anything nearby.
3-4 = "watz diz leava do?" Stumbles d6 via scatter dice. Anything it hits takes D3 impact hits. Can't move.
5-6 = "Noez, dat'z da boila relize kontrol!" Big template ontop of the Steampa, anything under it gets strength 3 hits. Can't move.
Having similar chart for attacks i.e giant style.
Mogsam