The Yoga Mummy (ドリル頭突き, Doriru Zutsuki, "Drill Headbutt"), also known as the Head-First Drill (in Super Street Fighter II Turbo: HD Remix) and the Drill Headbutt, is one of Dhalsim's unique attacks. It made its first appearance along with Dhalsim in the original Street Fighter II games.
Executed by pressing downward and heavy punch while in midair, the move consists of Dhalsim slowly twirling downward, spinning like a drill, and hitting the opponent headfirst.
Dhalsim also possesses a similar move known as the Yoga Spear.
This attack alongside Yoga Spear both became much more useful in the Champion Edition update, In World Warrior both attacks could only be done at the apex of his jump, lowering it's effectiveness. In Champion Edition Dhalsim could perform both attacks at any point of his jump, giving it properties similar to Rufus's Falcon Kick. Yoga Spear is probably more useful overall due it it's angle.