Fire Imp

The Fire Imp is a mage found in The Underworld.

Fire Imps will teleport around and shoot a spell called Burning Sphere (1HP, 25 attack power, 0 defense) at the player. Burning spheres travel through walls and can be destroyed if at least 1 damage is applied against them. Their attack pattern is identical to Dark Casters and Goblin Sorcerers. Fire Imps will die if they fall in Lava. If a player touches a fire imp, they will take damage as if they were burned. The obsidian skull does not affect this.

Imps drop coins and also Flower of Fire as a rare drop, as well as the Plumber's Hat.

They cannot spawn in tunnels three blocks high by two blocks wide. They can spawn on platforms but platforms do not count as a ceiling. If one tunnels deep enough with no open spaces around they will stop spawning altogether. This is an effective way to mine hellstone ore very quickly at the bottom of the map.

Fire Imps will sometimes spawn in lava and immediately teleport after taking 40 damage, making it appear as if they have spawned with half health.

Fire Imps shoot 3 burning spheres then pause for a second before teleporting and repeating, which goes on until you kill it. In addition; they will teleport early if they have been attacked. They will occasionally teleport on top of a player dealing damage. While flinching from being attacked they are unable to teleport or shoot, while also being unable to teleport or shoot while falling through lava. However, if they land on a block before they burn to death, they may teleport out.

Fire imps have a very high spawn rate.

It is recommended to bring a Cobalt Shield, because they remove knockback.

Trivia

 * Due to the Fire Imp's ability to teleport, a player can lure the Imp to the surface by using a Grappling Hook, or other device to quickly ascend while the Imp is following the player.