Yellow Submarines

The yellow submarines are one of the most notable elements in the Rabbids series, as well as the most iconic props next to the cows and pink toilet paper rolls. The yellow submarines are a form of spaceship or UFO the Rabbids use to invade various locations such as Paris and so on. In the first Rayman Raving Rabbids, the submarines were mostly used underwater and fired missiles at Rayman. In later games, the submarines could fly and ocassionally transform themselves into robots a la Transformers.

Rayman Raving Rabbids
In the original game, the submarines were piloted by Rabbids underwater. They launched missiles at Rayman and often released the Frog Rabbids (Rabbids wearing scuba masks). The submarines were designed to look like sharks, as the front of the submarines had red eyes and shark teeth painted on them.

Rayman Raving Rabbids 2
In Raving Rabbids 2. the submarines were completely redesigned. They could now fly around freely through anywhere the Rabbids pleased. The submarines now had mouths painted on them, so they could look more like Rabbids. One of the submarines could transform itself into a large metal robot (an obvious parody of Transformers) and launch plungers and missiles at the player in the FPS mini-games.

Rayman Raving Rabbids TV Party
Even though the submarines do not make a major appereance, they do make a cameo appreance in the mini-game Incredible But Stupid, where a Rabbid is surfing through space, sometimes a submarine can be seen floating around space.

Rabbids Alive and Kicking
In Rabbids Alive and Kicking, the submarines are slightly redesigned, the mouths are now made of glass, allowing the Rabbids to see through it while they're piloting.

Mario + Rabbids: Kingdom Battle
A Yellow Submarine Appear as a cameo in the Lava Pit with a drill in his face.

Rabbids Invasion (TV series)
In Mad Rabbid and the Secret of the Flying Submarine, Mad Rabbid discovers a Flying Submarine under the junkyard, where he and the Rabbids use to travel. There is also a robot named Secur-X that calls them "masters" and helps them. After the Submarine destroyed the junkyard, the Rabbids now have their sub as a new home for them while traveling around the world in order to, from what Mad Rabbid thinks, an island full of pretzels. For information see Flying Submarine

Trivia

 * The yellow submarines are an obvious reference to a popular song performed by The Beatles.