Super Saiyan 7 is the seventh and final form of the Super Saiyan forms. To obtain it, the user needs to have fully mastered their Super Saiyan 5 and 6 form. The form overall combine the skill of the 5th form and power of the 6th form, the looks of the 4th form, all while using the overall classic powers and color of the original Super Saiyan 1, 2, and 3.
The immense power of the form would literally tear even a Fusion apart, and requires two fusions. Example: Goku and Vegeta fuse into Gogeta (via Fusion Dance). Goten and Trunks then fuse into Gotenks (via Fusion Dance). Then both Gogeta and Gotenks perform the Fusion Dance, and fuse into a 4-in-one being (instead of the normally 2-in-one), Gogetenks.