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)