Opabinia was a strange animal that lived during the middle Cambrian period.
The length of Opabinia regalis from head to tail ranged between 4 centimetres (1.6 in) and 7 centimetres (2.8 in). The animal also had a hollow proboscis, whose total length was about one third of the body's and which projected down from under the head and then curved forwards and upwards. It ended with a claw-like structure whose inner edges bore spines that projected inwards and forwards.
The head bore five eyes: two on stalks near the front and fairly close to the middle of the head, pointing upwards and forwards; two larger eyes, also stalked, near the rear and outer edges of the head, pointing upwards and sideways; and a single eye with a shorter stalk between the larger pair of stalked eyes, pointing upwards.
Opabinia probably used its proboscis to search the sediment for food particles and pass them to its mouth. Since there is no sign of anything that might function as jaws, its food was presumably small and soft.