While in the Hyperbolic Time Chamber, Goku shows Gohan that he can surpass a normal Super Saiyan and can ascend to the next two levels.
EDIT:
Okay guys, look at this.
Here are the stages of a Super Saiyan;
False Super Saiyan - [Goku]
Super Saiyan - [Goku, Vegeta, Mirai/Future Trunks, Gohan, *Cell, Goten, Chibi/Kid Trunks, Gotenks, Vegito, Gogeta]
Ultra Super Saiyan - [Trunks, Vegeta, Goku]
**Ultra Saiyan Saiyan LEVEL 2 - [Trunks, Goku]
Mastered Super Saiyan - [Goku, Gohan, ***Vegeta]
Super Saiyan 2 - [Gohan, ****Cell, Goku, Vegeta]
Super Saiyan 3 - [Goku, Gotenks]
Full Power Super Saiyan 3 - [Goku]
Super Saiyan 4 - [Goku, Vegeta, Gogeta]
Ascended Super Saiyan 4 - [Goku]
* Cell is always shown in a golden aura, much like a SSJ. This is from his genes, so he is sometimes classed as a SSJ.
** Ultra Super Saiyan Level 2 is NOT the second stage after a SSJ2. It is the third stage after a SSJ - [ Super Saiyan, Ultra Super Saiyan, Ultra Super Saiyan Level Two, Mastered Super Saiyan ]. This was achieved by only two people.
***It is not shown when Vegeta reaches the Mastered Super Saiyan state but it is higly likely that he did during his 7 years training after the Cell Games.
****After blowing himself up on North Kai's planet, he comes back to Earth even stronger than he was before. He appears to have static/lightning which is a key apearance feature for an SSJ2.
Tags: DBZ Dragonball Z Goku Super Saiyan SSJ USSJ USSJ2 Gohan
