Ecco the Dolphin by Levyrasputin

The protagonist of a surprisingly complex series of video games from Sega. He's no Sonic the Hedgehog. And there's nothing wrong with that.

Ecco's fellow dolphins are abducted by aliens, and it's up to Ecco to travel the oceans, backwards and forwards through time, to try and rescue them and save the Earth. And the aliens are horrifying. Their leader, the Vortex Queen, is one of the most unexpectedly terrifying monsters you'll find in a 90s video game. The background was inspired from the last level in the first Ecco game, "Welcome to the Machine."