Octoper OA (オクトーパーＯＡ Okutōpā OA?) (Octoboss in Mega Man for Game Gear) is a giant octopus robot that appears as the sub-boss in Wave Man's stage, appearing while Mega Man is using the marine bike. It bobs up and down in the water, and can only be damaged in the green core on his forehead. When its face appears, it will shoot energy balls from its mouth. The Octoper OA in the Mega Man Game Gear game is smaller than the one in Mega Man 5 on the NES.
- Octoper OA's name is a modification of the word octopus, and is similar to the word October (オクトーバー). Because of this, his name is mistranslated as "October" in the Navi Mode of Mega Man: Anniversary Collection.
- Octoper OA would also have been able to attack with a tentacle, but this was removed from the game.
- Octoper OA is the only sub-boss in Mega Man 5.
|Mega Man (Game Gear)|
|Bright Man • Stone Man • Star Man • Napalm Man • Wave Man • Toad Man • Dr. Wily|
|Mega Man's Weapons|
|Mega Buster • Flash Stopper • Power Stone • Star Crash • Napalm Bomb • Water Wave • Rain Flush|
| 100 Watton • Apache Joe • Asteroid • B Bitter • Baby Metall • Bomb Thrown • Bounder • Changkey Maker • Dachone • Daidine • Dompan|
Gas • Giree • Gyotot • Hirarian 427 • Irucan • Jet Bomb • Lyric • Metall Cannon • Metall Mommy • Minoan • Mizzile • Mousubeil
Power Muscler • Puyoyon • Rackaser • Ratton • Rider Joe • Rock Thrown • Rolling Drill • Scworm • Sniper Armor • Space Metall
Springer • Swallown • Subeil • Sumatran • Taban • Tatepakkan • Teckyun • Tondeall • Toss Machine • Totem Polen
Twin Cannon • Yudon • V
|- Sub-bosses -|
|Escaroo • Octoper OA|
|Extra Life • Life Energy • Weapon Energy • Energy Tank • Mystery Tank|
|Battan • Bottomless Pit • Force Beam • Spikes • Mega Man (Game Gear) Damage Data Chart|