The spacecraft seems to be a triangular prism with a white metal coated floor and a large transparent window on one of its sides for Bubbles to look out of. The spacecraft is equipped with an old style bathroom for unknown reasons. What is very unusual about this spacecraft is that the glass window is the only part that can be seen outside of the spacecraft; probably because of some type of inter-dimensional technology.
Role in movie
While SpongeBob and Plankton were time traveling in their Time Machine, they accidentally arrived at Bubbles' spacecraft in the "middle of space". While there, Bubbles asked them to watch the cosmos for him so he could take a potty break; during that time SpongeBob and Plankton crashed Saturn and Jupiter into each other which made Bubbles angry and started shooting laser beams at them.
It is unknown who built this spacecraft.
In one scene, when SpongeBob and Plankton are thrown in the air after almost being zapped by Bubble's laser, bubbles are shown, even though this is not located in the ocean. It is also unknown how sea creatures like SpongeBob and Plankton are able to breath in this spacecraft.
Bubbles's spacecraft is probably influenced by the TARDIS from Doctor Who.