Acanthaster planci are red colored echinoderms protected by
thorn-like spines. They grow to a diameter up to 40 cm across.
They have 12-19 arms extending from their center. These animals
do not have a head, and are pentamerically symmetrical about the
axis of the mouth. Acanthaster planci have tubed feet, or
branched tentacles arranged along each arm that function in gas
exchange and food gathering (Schmid, 1998; Perrins and
Middleton, 1985; Encyclopedia Britannica, 2000).