Underwater Alien
This little guy is a Lined Bubble Shell (Bullina lineata) photographed in Narooma on the East Coast of Australia & is only about 10mm long.
Bubble shells are a small Opisthobranch (underwater snail) which can be found throughout the tropical & subtropical waters of the Indian & West Pacific Oceans.
The frills on each side of the head are head shields & protect the animal when it is burrowing under substrate in search of prey.
The small black dots that look like eyes are photo receptors