The Fire Skull (in-game name Liekkiö)
These are occasionally encountered in the Mines and Coal Pits.
They follow the player and try to get close for a melee attack. If hurt, they will scatter gunpowder all over the place, dealing low damage. This also tends to damage the surrounding terrain, which may be useful, but can also overwhelm the player if they are fighting it near flammable objects.
If the player turns into this enemy using Chaotic Polymorphine, they will catch on fire upon returning to normal. This may be a bug.