Flashlight fish have glowing lanterns below their eyes

Flashlight fish, also called lanterneye fish and scientifically photoblepharon (light-eye), are strange and wondrous creatures best viewed during a night dive in the Pacific.

Here's what they look like in daylight. The white sac below their eyes contains bioluminescent bacteria.

Here is a detailed video in Japanese:

These beauties were filmed off the Solomon Islands:

Lantern eye fish living in the deep sea (YouTube / Michiko Hiratsuka)