The Fire Imp is an enemy found in The Underworld.
Fire Imps will teleport around, seemingly at random, and shoot fireballs at the player. The fireballs travel through walls and can be destroyed if at least 8 damage is applied against them. Destroyed fireballs can drop coins, health, and possibly other common items. Their attack pattern is similar to Dark Casters.
If positioned properly with a strong enough pick, it is possible to ignore them while mining in a fashion similar to deflecting Meteor Heads.
If you kill a Fire Imp there is a chance that they will drop a Flower of Fire.
Ironically, Fire Imps will die if they fall in Lava.