Power Rangers

Neptune's Daughter (8x34)

Air date: Nov 11, 2000

Aquafiend, the only demon capable of surviving exposure to free-running water, swipes the trident of King Neptune, ruler of the seas. His daughter, Marina the Mermaid, is granted human legs for a temporary period, and seeks out her love interest, Chad, to gain the Rangers' help in recovering the trident from the demons, who seek to destroy the Aquabase with it. After the trident is returned to King Neptune, Marina is allowed to alternate her time between the surface world and the seas, allowing her to continue her relationship with Chad.