Helmasaur

Small creatures that hide behind a mask that acts as a shell. Their weak point is their behind.

Twilight Princess
Helmasaurs make a return in Twilight Princess and are found in the Lakebed Temple and Hyrule Field.In addition to waiting for them to charge, dodging and slashing their backside, you can target them with the clawshot to remove the "helmet" and reveal an attackable creature.