The reincarnation of King Piccolo who's also his own son (say what?) is one of the finest characters in the series.
He also had one heck of a growth spurt.
One of the best fights is him versus Goku at the World Martial Arts tournament.
Then he gets his revenge on Goku in a lucky turn of events.
But then HE R GOOD GUY for the rest of the series.
So he trains while nobody's looking.
And he fuses with some random guy, and is strong enough to fight the King of the Universe.
Until that guy transforms again and again. Then he ain't worth much.
He does get powerful enough in the Androids saga. He was able to take on Dr. Gero.
Then he fused with Kami and became for a short time of course, the strongest character in the series.
He then meets Cell, and can't catch him.
So he decides to the kill the androids before Cell can absorb them.
Well we all have plans that never work out.
He is sort of useless and more a babysitter at the end of the series. But I do like this moment a lot.