Using the fire immunity badge to use the lava as a bouncy platform and to completely pass through Gargantua Blarrag (spl?) is actually really fun, it's almost similar to a kind of cheat Rareware would give you in Banjo-Tooie, kind of like Fallproof which makes just dropping from a high height like the top of the Grunty Industries building's roof a shortcut rather than instant death.