Hatchiyack was created by a Tuffle doctor named Dr. Raichi. Hatchiyack was created by the Tuffles hatred of the Saiyans and his mission was to kill the last living Saiyans alive. The Z-Fighters had a tough time fighting him until Goku found out that it takes Hatchiyack 15 seconds to charge his Ki and he was defeated. In an alternate ending Goku gathered energy for the Spirit Bomb and threw it at Hatchiyack but before the Spirit Bomb hit Hatchiyack, Goku used Instant Transmission threw an energy wave at Hatchiyack's face and grabbed Vegeta and teleported away, then finally the Spirit Bomb hit Hatchiyack killing him.
Hatchiyack's power is stated to be around Broly's power level, (actual quote from Goku, his power might be stronger than broly's, but...)