Holothuria thomasi, the tiger's tail, is a species of sea cucumber in the family Holothuriidae.

It takes the form of an elongated cylinder with rounded ends and can reach 2 metres (6 ft 7 in) long.

On the upper side there are papillae, thornlike projections, which are dark brown tipped with white.

[4][5] Holothuria thomasi is found in the Caribbean Sea, the Gulf of Mexico and surrounding areas.

The tentacles grab the detritus, sand, gravel and algae that it encounters and pushes them into its mouth.