Magma Burn, Boyler's Daydream, is activated by his ears, which, after friction, set him on fire, which causes an explosion that puts him into fireball form.
In this form, he loses his limbs but is covered in fire and his body gets rubber-like properties that allow him to move extremely fast by spinning, which lets him have enough momentum to bounce around.
If he's put out of this form, he cannot use it again for several hours.