Android 13

Android 13 (人造人間１３号, Jinzōningen Jū San) is Dr. Gero's thirteenth Android creation. He was designed to serve Gero's vendetta against Goku, who overthrew the Red Ribbon Army as a child. He made his debut in the film Super Android 13!.
Android 13 was created for the sole purpose of destroying Goku. In the original Japanese version of the film, his serious demeanor regarding this task is demonstrated in Android 13's personality, while in the Funimation dub, his attitude is essentially that of a stereotypical "redneck" (which his character design also appears to have been modeled after). In the dub, he scarcely refers to Goku by name, preferring instead to call him by such titles as "city boy," "son" or "boy."
In addition, the English dub provides a further glimpse into Android 13's psyche and to a small extent, humanity, when he lectures Trunks about how people have misused their free-will to create more sufferings like war, segregation and hatred; the original Japanese version and Chinese dub feature completely different dialogue from the character during this sequence. Also in Funimation Entertainment's dub, Dr. Gero's computer directly relays information to him, which is something only subtly hinted at in the original Japanese version of the film.

Android 13 is completed by Dr. Gero's self-aware supercomputer later than androids 14 and 15, who by this time are already taking up arms against Goku and Future Trunks. Upon his arrival on the Glacier, Android 13 confronts Goku, leaving Trunks and Vegeta to struggle against 14 and 15, shortly after which Piccolo intervenes to assist Goku, as well. Ultimately, androids 14 and 15 are defeated following Trunks and Vegeta's transformations to Super Saiyan, however even their deaths are fail-safe in Gero's plan, as 13 pauses to absorb components from 14 and 15, resulting in his fusion into Super Android 13.


 Super Android 13

 Vegeta is the first to attack the newly transformed super android, only to be quickly brought to his knees by 13's amazing new strength. Goku, Future Trunks and Piccolo's attempts are also foiled with little effort on 13's part. Becoming desperate to stop the android threat before he grows out of control, Goku is forced to prepare his ultimate weapon, the Super Spirit Bomb, whilst Vegeta, Piccolo, Gohan and Trunks distract 13. The Spirit Bomb's effectiveness is amplified when Goku makes a transformation to Super Saiyan during the process of gathering energy. Krillin states that only a calm-hearted person can sustain a Spirit Bomb, and when Goku transforms into his Super Saiyan form, his body absorbs the Spirit Bomb's immense energy. When 13 lunges at Goku, one punch from Goku sends the super android into the depths of the Spirit Bomb, where he is disintegrated by its ki.

Information from:
http://dragonball.wikia.com/