This picture above belongs to the Acorn Worm(Class Enteropneusta)These are cast that the worm excrete.Its look like cow dunk rite?^^This picture above is called the Fan Worm.(Family Sabellidae) It lives in a long tube made up of sand and mucus. The feathery stalks observed poking out of the worm .The rest of the worm remains in the tube .There are eyespots located on the tentacles and upon detecting light intensity changes,these worms would react completely into the safety of the tube.
This picture above is called the sea cucumber (Class Holothuroidea). It can also burrow, feeding on the detritus (tiny organic particles) in the substrate. The sea cucumber is considered as a gourmet food item in South East Asia.(in Chinese it is called 'hai shen')When threatened, they would expel a sticky white substance that hardens upon contact with the air.

This picture above is called the Hairy Crab.(Pilumnus vespertilio)It has fine hairs covering their bodies.This is an effective means of camouflage.Can u see it??