These incredibly beautiful little creatures are Hairy Squat Lobsters (Lauriea siagiani). They live on Giant Barrel Sponges and don't usually like to get their photo taken. They're a little bit shy :)

These squat lobsters are remarkably colored, with their intense pink body, purple spots, and bright yellow hairs that protrude in all directions.

Here's a really great video of one that decided to go for a walk around his home: