Dark Necrobat (known as Dark Dizzy in the original American release) is a Maverick Reploid and one of the eight selectable bosses in Mega Man X5. Based on a vampire bat, Necrobat was created by Sigma three years prior to the Eurasia Crisis. However, he somehow escaped from Sigma's control and went into hiding, but Sigma did not consider Necrobat a threat and made no attempts to reacquire him. Necrobat re-emerged and seized control of a planetarium in Sudan when the Maverick Hunters mobilized to combat the global Maverick outbreak. X and Zero arrived in search for a fuel source for the space shuttle that was to be used against the falling Eurasia Colony and Necrobat fought against them, only to be destroyed.
- Flight - Necrobat's large, powerful wings allow him to stay airborne for most of the battle.
- Batton Attack - Necrobat summons a swarm of Batton Bones to attack.
- Bloodsucking - Necrobat feeds on the energy of his opponent, draining their health and restoring his own.
- Dark Wave - Necrobat emits huge sonic waves that inflict heavy damage if not dodged.
- Dark Hold - Necrobat briefly stops time, granting him an opportunity to attack while his opponent is frozen. Both X and Zero can copy this ability.
Being based on a nocturnal creature, Dark Necrobat is understandably adverse to bright light. The Flash Laser and Chaos Flasher obtained from Shining Firefly will flash-fry his circuitry.