Moffle, of course, is based off Bonta-kun, Kaname's favorite mascot from Gatoh's previous work Full Metal Panic!. Lampshaded by Seiya, to the point that he calls Moffle "walking copyright infringement".
Bonta-kun happens to be by the same author, who did acquire the rights.
He goes far enough to use the Dragon Slave attack from Slayers, though Seiya fortunately stops him before it kills a dragon.
The blue crocodile mascot Crocky is an obvious ripoff of Totodile.
Isuzu's general demeanor while she is unable to lie thanks to the "Heart-on-One's-Sleeve" bean is just like Fletcher in Liar Liar right down to bashing her head against any nearby surface when she's about to say something embarrassing.
Moffle, Macaron, and Tiramie's "You Maggots" routine to the new part-timers in episode 6 is taken word-for-word from Full Metal Jacket.
Jaw, the shark employee, is an obvious reference to Jaws. He even briefly shows the iconic look when he's introduced.
During episode 8 of the anime, Seiya (actually Macaron in disguise) gets right in his teacher's face. This looks very similar to a scene in another of KyoAni's adaptations.
When Latifah gets captured by Ironbeard, the scene looks awfullyfamiliar.
In the dub of Episode 7, when Tiramie switches to the pirate's side, he says "Resistance is futile!"
