Super Buu(with Gotenks, Gohan, and Piccolo absorbed)(Dragon Ball Z Profile)

This is Super Buu after absorbing Gohan. This is Majin Buu's most powerful form. In this form, he's only outclassed by Super Vegito, making him the "Omega Shenron" of Dragon Ball Z, though he's not the last of Buu's form to appear in the series.

Whenever Majin Buu sucks up a warrior, he frequently takes on some of his/her outside looks aside from gaining his/her abilities, and absorbing Gohan is no exception. His facial features are more detailed and humanoid in this state, and he speaks perfectly and clearly in an intelligent but menacing manner, often mentioning about deaths to occur.

Super Buu was unlucky for not being able to finish off Gohan before Gotenks defused into Goten and Trunks inside his body, maybe this was due to the fact that Gotenks' cockiness was dangerously affecting him, for he was so confident that he'd take his time playing around with Gohan before he could deliver the finishing blow. As he was about to hit Super Saiyan 3 Goku, he suddenly began to mutate into a weaker being featuring Piccolo's familiar clothing - losing a huge amount of power that made him way inferior to either Goku or Gohan. Although it seemed that Buu was doomed, a piece of goo from the tentacle of the back of his head that was previously cut off by Goku's Destructo Disk happened to be lying right behind Gohan, a place where Buu would want it to exactly be. The goo expanded itself and engulfed Gohan, like it did to Piccolo and Gotenks, merged with Buu's body, and transformed him into "The Mightiest Majin".

This mean, arrogant, and dangerous ancient-beast is arguably the strongest villain that's appeared in the series(with the possible exception of Hirudegarn). Super Buu was already so powerful after absorbing Super Saiyan 3 Gotenks and Piccolo, able to defeat Gohan twice even after Dende healed him to be as good as new, and he was able to immediately gain the upper-hand as soon as engaging himself in a fight with Super Saiyan 3 Goku(albeit Goku was paying more attention to Gohan to find the earring and fuse with him). However, after he absorbed the much more powerful Gohan, his power became so overwhelming that he was able to easily pound two angry and serious Super Saiyan 2 into oblivion in a few seconds.

In this state, Buu's power is great enough to cripple even Super Saiyan 3 Goku with relative ease, and Goku knew this well. Also, in this form, there is no time limit for which he can remain in the form, in contrast to his previous transformation, which makes him as unstoppable as he is frightening, and with the combined power of the two boys, Piccolo's and his impressive intellect, and the almighty Gohan's added to Buu's own, it would seem that comparing Super Saiyan 3 Goku to Super Buu is like comparing a kitten to a tiger. There's virtually no difference between his power and Vegito's(base form), considering the fact that he was able to fight almost evenly with Vegito during the first portion of their battle and was pushing Vegito to try seriously in blocking and evading his punches.