Rou Dai Kaioushin
Centuries ago, he used to be quite handsome by his own standards, but a hideous witch came up to him and stole one of his Potara Fusion Earrings and put it on. Ro Dai Kaioushin was instantly combined with the witch permanently. While he lost his looks, he gained more magical power. In the Majin Buu Saga he sacrifices his life so Son Goku can live, and gives him the Potara earrings to fuse with Gohan on Earth. However, as he was already residing in heaven, his death had little effect aside from producing a halo over his head.
In the Baby Saga of Dragon Ball GT, he helps Goku become much stronger by helping him regrowing his tail, a painful process involving a giant set of pliers. Source: Wikipedia