You were way scarier than the last sea monster.
As the wet blanket of the group, Rex (Wallace Shawn) rarely gets to do anything more than fret and accidentally cause problems due to uncontrollable anxieties. So why not let him have some fun, albeit against his better judgment? Knowing this outcome would only be possible if he was removed from the usual Toy Story group and thus rendered “cool” by not having anyone cooler to compare, Mark A. Walsh and Dylan Brown let Bonnie isolate him in the tub with her floating menagerie of bubble-bath friends. Because they need water to move and only receive about fifteen minutes of it a day to entertain themselves, Rex brings something to the table that they sorely need: arms with which to turn the faucet. All hail the Partysaurus Rex.
The result is a cute tale of self-empowerment that should have rejected the desire to use peer pressure as a means towards procuring it (Don Rickles‘ Mr. Potato Head calling Rex “Partypooper Rex” becomes a repetitively subliminal message pushing the dinosaur to go against his instincts). I get the want for a literal reason rather than simply letting an opportunity at a fresh start be enough, but you risk legitimizing Potato Head’s insult as a source of psychological coercion by constantly showing it when the taunt should have remained a solitary catalyst for Rex’s frustration and drive to have fun. Let it push Rex to create his own impulse to act upon (a positive evolution of identity) instead of having Potato Head’s abrasiveness directly change him (negative reinforcement).
Luckily the central event wherein Rex facilitates the needs of his new bath friends is enjoyable enough to look past this misstep in motivation. Watching him turn the water on and do everything possible to ratchet up the rave-like atmosphere of these wild new characters that know nothing but short and intense bursts of pure elation is great. BT supplies the trance music and glow monsters provide the strobe lights for a night of unencumbered excess removed from Bonnie’s imagination that these creatures imprisoned by their physical shortcomings will never forget. Rex becomes a God-like figure to them—an unwitting Van Wilder-type who lets them be themselves when the world would have otherwise left them to wait for supervised assistance that could never conjure the same unbridled insanity.