From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
ReaCoom calls out the name of the attack and elbows his opponent on their head, knocking them down to the ground.
ReaCoom used this attack in his battle against Vegeta on Planet Namek after exchanging blows with the Saiyan prince. Vegeta used a flurry of punches and kicks against ReaCoom, however, blocked most of them. After ReaCoom told the Saiyan prince that he was pretty good, he delivered an elbow hit to Vegeta's head and knocked him down.