This is from an old Games Workshop game, once published in White Dwarf #57.
I found this while cleaning out my attic. Don’t own the model sadly..
Anyway, I made a PDF of the rules for the Great Gargant
Ork Gargants are an extremely varied lot, with no two ever being exactly alike, as is common with seemingly slapdash Ork technology. Thanks to the frenzied imaginations of the Mekboyz building them, Ork weapons tend to be haphazard, unreliable and noisy. When they work, however, they can inflict gruesome damage. Gargants are commonly equipped with at least one close-combat weapon, because charging in and bashing heads is considered to be a very “Orky” thing to do.