The fusions are Gotenks which is Goten and Trunks. Gogeta which is Goku and Vegeta with the fusion dance. Vegetto which is the fusion between Goku and Vegeta with the fusion earrings. These are the fusions. Gotenks can go Super Saiyan 1 and Super Saiyan 3. Gogeta and Vegetto can go all of the Super Saiyan levels.
There are three fusions
This is the fusion technique for the Kaioushins this technique is supposed to be a lot better then the fusion dance. For this type of fusion to happen the two people must wear the Potara earrings on different ears. This type of fusion is supposed to be permanent but being absorbed into a magical being (like Majin Boo)can result in the fusion to wear off. Each person can only have one of these fusions in a lifetime.
This is a Fusion performed by two people doing a dance the two people must do the same moves at the same time the slightest mistake can result in a really messed up Fusion like Fat Gogeta. After performing the dance correctly it will result in a new person that will be more powerful then the two separate. A side effect of the fusion is the new person is very cocky. The two people must be similar in size, build, and their power level must be the same this is very important but this is not a problem since most of the Z warriors can control their power level. The fusion will last for Half an hour but is shortened while fused in SS 4 form. After the fusion ends there is a one hour waiting period before the fusion can be performed again.
Nameks have the ability to Merge or Fuse but is a little different then the rest of the fusions. The way it works it when the two Merge into one person one of them is in control and is the same person just stronger and has the knowledge of the other. The personality of the one that isnít in control but influences the other person.