Launch was a very memorable character of the original Dragon Ball anime and one of the few somewhat notable characters to be totally left out of Dragon Ball Z. Her name is actually a pun on the English word lunch.

She has a Dr. Jekyll/Mr. Hyde thing going on. As when her hair is blue, she’s super sweet and gentle. Very easily manipulated by Master Roshi into letting her be his eye candy.

But when her hair is blonde, she is a total absolute biatch. Luckily, for most of the fighter characters, she eventually becomes too weak to even make a notable injury.

Near the end of the original anime, she starts to crash hard on Tien Shinhan, but nothing ever seems to come about it.

And the main reason why is that Akira Toriyama forgot she existed and thus she got lost in the transition from Dragon Ball to Dragon Ball Z.