Undertow is the secondary antagonist of "The Little Mermaid II: Return to the Sea". He is a shark who works for Ursula's sister Morgana. For the most part, he is miniaturized due to King Triton. He is voiced by Clancy Brown

Later, in an attempt to eat Tip and Dash (though he does have Tip inside his mouth), he is forced into smashing his teeth in an iceberg and his teeth break.