The Bulette-Mutation

This creature looks exactly like an ordinary bulette. It is the product of magical and biological tinkering by a wizard named Vessaran, who grafted in venom glands that let it breathe fire.

It hunts like any bulette, attacking whatever it thinks is edible with bite and front claws. Once a foe has actually wounded it, there is a 65% chance each round that it also breathes a cone of fire 20 feet long and 5 feet wide at the base, dealing 3-18 damage; a successful save vs. breath weapon halves it. It can breathe up to four times per day.

Its armor matches a normal bulette's: AC -2 at the heavily armored head, AC 6 in the soft spot under the crest, and AC 4 at the tiny eye area. Hurt or cornered, it can leap up to 8 feet and attack with its rear feet as well, but never breathes fire in a round when it jumps.

Territory and temperament are those of a normal bulette. Should it escape its creator's lair, the DM may let it find mates and breed; in that unlikely event, half of the offspring are ordinary bulettes and the other half are fire-breathers like itself.

Turned loose in the woods near its maker's home, it quickly undermines or burns large tracts of forest, and within 1-3 weeks, unless killed, it moves on to nearby human lands, preying on people and livestock, setting houses alight, and bringing down forts with its tunneling. Its armor can be made into shields just as a normal bulette's can.