Panulirus penicillatus is a species of spiny lobster that lives on shallow rocky and coral reefs in the tropical Indo-Pacific region. Common names for this spiny lobster include variegated crayfish, tufted spiny lobster, spiny lobster, Socorro spiny lobster, red lobster, pronghorn spiny lobster, golden rock lobster, double spined rock lobster and coral cray. It has a very wide range and the International Union for Conservation of Nature has assessed its conservation status as being of "least concern".

Spiny lobsters differ from true lobsters in having large spiny antennae and lacking pincers on their front legs. Panulirus penicillatus grows to a maximum length of about 40 centimetres (16 in), but a more normal length is 30 centimetres (12 in), with males growing to larger sizes than females. There is a group of four strong spines joined at the base, attached to the plate immediately in front of the carapace to which the antennules are attached. The colour of this spiny lobster is variable, ranging from yellowish-green to rusty-brown or bluish-black. There are small white spots on the carapace and abdomen and a pair of larger white spots near the outer edge of the first abdominal segment. The legs are dark green or red with yellow longitudinal stripes. The antennules are not banded.