This is Dr.Gero in his android form. He turned himself into an android to prevent himself from dying. He was killed after Android 17 and Android 18 turned on him after activating Android 16, an android that Dr.Gero might have someday programed to kill Goku.
On May 6th he appeared on a island 9 miles south west of south city and took away Yamcha's energy. Android 19 fought goku but the heart virus Trunks warned him about gave 19 the upper hand. Vegeta appeared and transformed into a super sayian and easily beat 19. Dr.gero then left and took away some of piccolo's energy. Then after he fought piccolo he saw bulma coming and blasted her flying car.He then ran but while he was escaping he ran into krillin and defeated him but didn't kill him. He then activated 17 and 18 then they killed him.
Dr.Gero came back in Dragonball GT when he and Dr.Myuu teamed up in Hell to create Super 17, but dr.myuu soon programed Super 17 to only obey him. Super 17 later killed Dr Myuu and tried to kill Goku but with the help of 18 they killed 17.