That's a Nejiron.
Nejiron is an enemy that appears in Majora's Mask.
Nejiron appear in Road to Ikana and in the Stone Tower Temple. They're rock-like creatures (similar to Goron) that dig out of the ground. They attack by rolling into Link and crushing him. Long-range weapons are the best way to kill them as they explode when defeated, which does damage to Link if he is in range.