|~ Gulpo, NiGHTS Archie Comics.|
Gulpo is a giant, blue piranha, who has three yellow and orange spikes around his face, five on his back and four on each of his fins. His belly is white and his tail is blue and purple.
NiGHTS into Dreams
Gulpo will stay inside a tank, surrounded by red fishes which NiGHTS can use to launch themself into Gulpo. The player must find the fishes pointing at Gulpo to damage him.
Sometimes, Gulpo will surround himself with dark energy orbs and shoot them at the fishes. This will make the fishes be surrounded by a dark energy for a few seconds. If NiGHTS tries to use these fishes in this state, they will be damaged.
Also, when Gulpo is releasing his energy orbs, small eletric waves will pass through his body. These waves will hurt NiGHTS if they fly into Gulpo in this state. Getting damaged by any of Gulpo's attacks will teleport NiGHTS back to the outside of the tank.
Sometimes, Gulpo will turn upside down after getting hit. Attacking Gulpo in this state will give him more damage. Gulpo usually takes from five to six hits to be defeated, however, it's possible to defeat him in three hits if the player keeps attacking him while he is upside down. 
After the battle, Gulpo isn't seen again.
Gulpo's battle takes place in the deeps of the ocean around a transparent and cylinder tank surrounded by fishes.
NiGHTS Archie Comics
In the Archie Comics series, Gulpo makes a small appearance only in the second issue. Claris was eating lunch at the Twin Seeds Museum with Roger, who was dualized with Reala. Reala was seeing everything through Roger's eyes and noticed that Claris felt disgusted over a fish identical to Gulpo on her meal.
Later, a Shleep makes Claris fall asleep and she is transported to a giant aquarium in her dreams where she is attacked by Gulpo. NiGHTS was dualized with Elliot and fighting Jackle when they hear Claris screaming for help and goes assist her, unfusing with Elliot and leaving him alone with Jackle.
NiGHTS and Claris start fighting Gulpo, but as NiGHTS has to come to back to help Elliot, they decide to leave Claris with a message on the glass telling her to sing. When Claris does that, the aquarium's glass breaks and Gulpo becomes unable to fight as there's no more water for him to swim in. As Claris leaves the aquarium, Gulpo starts shrinking to the size of a small fish. Clawz appears and eats Gulpo alive for his failure. Unlike the other second level Nightmarens, Gulpo doesn't make another appearance. It's unknown if Gulpo could come back or be revived as he was eaten by Clawz. However, considering Puffy was crushed against the wall and later reappeared, it's possible that he could.
- Christmas NiGHTS into Dreams: Gulpo's render appears in the concept art.
- Sonic Pinball Party: Gulpo made an appearance in Sonic Pinball Party as a boss. Curiously, instead of being the boss of the Mystic Forest table, he is the boss of the Frozen Bell one. To defeat him, the player must make the ball paraloop him enough times under 180 seconds.
- Sonic Lost World: Gulpo appeared as the third boss of the Nightmare Zone DLC of Sonic Lost World, where he is ridden by Master Zik. Gulpo will chase Sonic across the stage and shoot spike balls at him. To defeat Gulpo, Sonic must make him fall into a hole.
Descriptions and Profiles
Japanese bio (NiGHTS into Dreams)
"This fish-type Second-Level will swallow anything up completely with his huge mouth. His form is ferocious, but his personality is surprisingly calm. Knowing his weakness is his slowness, he’s set up traps all around his body to catch his prey."
- In Burning Rangers, there's a giant mechanical fish that resembles Gulpo in some bits.  It's possible that Gulpo's 3D model was used to create it.
- Girania from NiGHTS: Journey of Dreams is similar to Gulpo, though only appearance wise, as both are fish-like second level boss Nightmarens.
- In the NiGHTS into Dreams game files, Gulpo is nicknamed "M6:MONSTER-FISH".