Voltron: Legendary Defender

In 2016 the web-television reboot of GoLion and Voltron: Defenders of the Universe premiered. The show follows the adventures of the distinctive five robot lions who can combine to form Voltron for the sake of defending the universe from evil. In this show the original five pilots of the lions are from Earth, and throughout the series get to travel to various worlds and meet various aliens all over the galaxy.

In season 2 episode "The Depths", Hunk and Lance of the Yellow and Blue Lions end up crashing in the ocean of an unfamiliar planet. There, they encounter the merfolk of a small village, who are lead by Queen Luxia. The merfolk welcome Lance and Hulk warmly -- perhaps a little too warmly. There's something suspicious going on with the merfolk, who seem to want to keep the two humans there forever.