Fire-breath

Fire-breath is an ability that several Transformers with reptilian or monstrous beast modes have for combat in their alt modes.

Transformers: Fall of Cybertron
As Shockwave's prized test subject, Grimlock received numerous upgrades and powers, including the ability to breathe fire in his Tyrannosaurus form.

"The Island of Misfit Tech"
A mechanical bull developed for humans to ride could shoot fire from its nostrils.

"Suspended"
Crazybolt can breathe fire in his robot mode, or spray a trail of flaming exhaust in vehicle mode.

"The Golden Knight"
Flamesnort can breathe fire in his robot mode, too.