Plankton's tank is green with some yellow and red on different parts of it. It appears that the inside of the cannon is red and the tip is colored yellow to look like his eyeball.
The giant robot looks similar to Plankton, except for the massive size difference. The robot has two large arms, two long legs, a large red eye, and a cylindrical body similar to Plankton. Plankton can sit in the robot and control it by pushing the antenna-like levers.
The tank robot appeared as a boss in the first level.
The SpongeBob Movie: Sponge Out of Water
The tank robot is first dropped from Air Plankton when its wings fall off the condiment blaster. It then starts to shoot potatoes at the Krusty Krab. SpongeBob continues to shoot ketchup and mustard while Patrick is still holding the mayonnaise. Eventually, Patrick cannot hold the mayo any longer and throws it at the tank, stopping it.
The tank robot appears trapped in slime in the background of the Bikini Bottom Boogie Nights race track.
Plankton's tank robot is the only character in SpongeBob HeroPants to have an actual boss fight. The other "boss fights" for Squidasaurus Rex and SpongeBob's mind are simply a chase sequence and a normal level respectively.