Hellbat

Type	Flying Enemy
Environment	The Underworld
AI Type	Bat AI
Damage	35/70›62/105›93
Max Life	46/92›100/138›150
Defense	8
KB Resist	20%/28%/36%
Banner	Hellbat Banner
Immune to
Coins	1 SC20 CCPre-Hardmode: 3 SCHardmode: 2 SC40 CC
Hurt	https://terraria.wiki.gg/wiki/File:NPC_Hit_1.wav
Killed	https://terraria.wiki.gg/wiki/File:NPC_Killed_4.wav

The Hellbat is a pre-Hardmode bat enemy that spawns in The Underworld, and are pesky creatures that can kill characters who are using early-game gear. Though they cannot fly underwater or through lava, they take no damage from making contact with either.

In the Get fixed boi(Desktop, Console and Mobile versions) secret world seed, it drops lava upon death.

Trivia

Unused animation frame

Hellbats, as well as Jungle Bats, Cave Bats, and Spore Bats have an unused frame in the animation that seems to depict a Hellbat hanging upside down. This may mean that bats were originally planned to be able to hang on ceilings but was later decided against.
(Desktop, Console and Mobile versions) Despite being a bat, it cannot inflict Feral Bite in Expert Mode. Only Cave Bats, Jungle Bats, Giant Bats, Spore Bats, and Giant Flying Foxes cause this debuff.
Its name, as well as its Underworld environment, are likely references to the saying "like a bat out of hell".