Sergeant Trump resembles an oversized turtle-like creature. He has a purple body with a yellow, trumpet-shaped mouth, has a large belly-button, wears a black helmet and has a black shell on his back. His eyes are completely black in color.
His EX appearance has him instead recolored blue instead of purple. He also dons a sturdier-looking, red helmet with spikes and a red back shell too.
Once Kirby and his friends go through a door, they'll find themselves in a submerged, aquatic room with a dark background and purple floor. A small switch is seen in the middle of the floor. When pressed, the area will explode, revealing a circular battlefield underwater. Sergeant Trump will float down and become enraged, starting the battle. Trump is located on the far front of the circle and is pounding the ground while doing horn-like sounds. The sounds make the stage tremble which make rocks fall down onto the stage. Electric Jellyfish will also be dragged by the current of water created by the huge turtle. The current of water will push Kirby and his friends back to the spiked wall behind them. To hit Sergeant Trump, use your copy ability to reach him and hit him (only ones usable underwater are Hammer, Spear and Sword) or swallow the Jellyfish coming and shoot them back at him. When his HP goes down to half, Trump will fall down in the floor, apparently "dead". A current of water that throws Kirby and his friends upwards appears and leaves the characters in a coast-like area.
In the coast part, there will be a large sentry post and Sergeant Trump will once again appear in it. He'll signal numerous enemies to swarm the battlefield, Kirby and his friends are in. He'll also shoot spiked balls into the stage or belly slam himself in the stage, creating shockwaves. To get a hit on him, wait until he belly-slams on the stage and let him have it. Shotzo cannons are mounted in the other sentry posts that'll shoot cannonballs at you as well. Once the sergeant's defeated, he'll yield the key to the castle that Drafero took over.
A stronger and more dangerous version of Sergeant Trump called Sergeant Trump EX is a boss in the EX mode of Story Mode. This version can make stronger currents, instead of Jellyfish, spiked fish will appear, stronger enemies are seen in the second phase and the Shotzos mounted on the posts are instead Giant Shotzos.
- Sergeant Trump was actually sent to guard the Obsidian Oceans with his army by Drafero.
- Sergeant Trump's overall appearance resembles a 3D version of a Tortletummy, a mini-boss faced in Kirby Mass Attack.