From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Fusion Dance is a supportive technique that was introduced by Son Goku in the Fusion Saga. His son, Son Goten, fused with Trunks Brief in order to create Gotenks. The purpose of the Fusion Dance was to temporarily merge two bodies into a single, superior entity.
To correctly perform the Fusion Dance, the fusees must create a perfectly symmetrical image of one another. The Fusion Dance is a short series of poses that are performed by two characters of equal power levels, roughly equal size and same race. In the series, the result of a correctly performed Fusion Dance is a superior being whose power is multiplied severalfold over that of the individual fusees. If one character performs the dance wrong, then it will result in an obese character who is much weaker than either fusee individually. If the timing of the poses is off, it results in a sickly looking Fusion who is also much weaker than each fusee individually. Regardless, the fused character possess mixed physical traits of their original counterparts. If they synchronize their dance correctly, it results with a very powerful being. Additionally, all end products of the Fusion Dance seem to acquire the same attire: white pants, a sash, and a vest with yellow or orange padding around the shoulders and neck.
Only one character in the original series has been seen as a result of the Fusion Dance; his name was Gotenks, being a Fusion of the characters Goten and Trunks. Even though there was only one in the original series, one other fused character appeared in a Movie and in Dragon Ball GT. In Dragon Ball Z Movie 12, Gogeta is born from Goku and Vegeta, however, he was first given the name Veku upon being incorrectly fused. The second time, he was correctly made and given the name Gogeta. Gogeta appears as a Super Saiyan 4 in Dragon Ball GT, and is the most powerful character in the universe. The total Fusion time lasts about 30 minutes, depending on the amount of ki that is used. After that, it takes the character's bodies another hour before they are able to fuse again.
The dance itself is explained by Goku in Dragon Ball Z Movie 12 as combining elements of both traditional fighting poses and water ballet. The performers must visualize two rivers flowing towards each other that get closer as they approach each other, then converge at two single points; the points collapse under the pressure and the two rivers flow into each other, becoming one. The movements – right down to the fusees' breathing – must be perfectly synchronized and symmetrical or the Fusion will fail. The fusees must also equalize their power levels.
Characters created via Fusion Dance
- The Fusion Dance lasts for 5 minutes in Dragon Ball Z: Buu's Fury rather than the normal 30 minutes. The timer will not go down on the overview map.
- If a player engages the Fusion Dance in Dragon Ball: Raging Blast, occasionally the computer-controlled fusee will stand still with their arms out in a cross fashion (known by gaming and 3D modeler veterans as the "T-stance" or "blind stance") due to a glitch in the programming. This does not, however, affect the Fusion.