Hercules and the Son of Poseidon

Hercules and the Son of Poseidon is an episode of Hercules: The Animated Series. It aired on November 16, 1998.

Summary
Poseidon introduces Hercules to his son Triton (Chris Elliott), a sea prince who wants to go to Prometheus Academy with him. It turns out Triton is somewhat of a nerd, wanting to be like his cousin; he has considerable acrobatic skills but terrible balance and timing, much like Hercules himself, causing him to be a constant source of humiliation. Icarus and Cassandra remind Hercules that he and his cousin are not so different, so he tries to apologize. Overhearing what his cousin thought of him, Triton has stolen Poseidon's trident and accidentally unleashed a sea monster. The two cousins team up to defeat the monster, and Poseidon arrives to take back his trident, not punishing Triton thanks to Amphitrite intervening.