Violet Sea Apple

Found over rubble and sandy areas, of coral and rocky reefs, rich in algae and seagrass.
They feed nocturnally on plankton.
Widespread Western Pacific, East Indian Ocean

When disturbed, sea apples, can projectile vomit their entrails from both ends, and can also consume large amount of sea water so they double in size.

Some sea cucumbers crawl around on the bottom slowly filtering sand through their tentacles to gather food, while others spread their tentacles above them to capture plankton. A number of sea cucumbers feed nocturnally while others feed by day.
There are sea cucumbers that hardly move while others are more active often perching on tall sponges to feed.
Sea cucumbers often attract hitch-hikers like shrimps and crabs that crawl over their skin, also pearlfish that enter via their anus.
As a means of defence sea cucumbers can expel their intestines or respiratory organs in the form of sticky threads, but these can quickly regenerate.
Juveniles often mimic sea slugs.
Some types of sea cucumbers are edible and considered a delicacy in the Far East countries.