|Home world:||Planet Naltis|
|First Appearance:||Ultraman Dyna episode 33: "Star of Peace"|
|Affiliation:||Alien Naltis (Master)|
Subtitle: Biological Weapon (生物兵器 Sebutsu Heiki)
- Total length: 164 m
- Weight: 180,000 t
- Origin: Planet Naltis → D7 warehouse of Bay Area
Once Alien Naltis fused with Menorfa, the blob monster grew extremely large, giving Asuka no other choice but to turn into Ultraman Dyna. Once the battle began Dyna had an extremely difficult time doing anything to Menorfa. When the Solgent Ray was unable to Hasumi noticed a bruise on Menorfa from where he threw a metal pipe from when the blobish monster was growing. Once this area was hit Dyna went into Strong-Type and executed the Dyna Drill, destroying Menorfa and Alien Naltis.
- Menorfa resembles Balloonga from Ultra Q.
- Suit actor: Koji Mimura, Toshio Miyake
- Menorfa's tentacles were reused from Diplas' tail.
- Menorfa's roars were reused from Gagi.
- Expand: Menorfa can expand it's body indefinitely after fusing with Alien Naltis. This allows it to regenerate from just about any attack, use sections of his body as battering rams, and reflect beams as strong as Ultraman Dyna's Solgent Ray.
- Energy Balls: Menorfa can launch white energy balls from its body.
- Electricity Emission: Menorfa can emit electricity all around its body.
Menorfa cannot regenerate from hits while growing, and if a hard enough attack is executed from where it's bruised Menorfa will die.