Regigigas is a wild normal-type Pokémon who appeared one time in the anime.
When it first awoke Brandon tried to catch it but Regigigas fought all three of his legendary Golems at the same time. Pokemon Hunter J stopped him and tried to catch it her self. Brandon, Regice, Regirock and Registeel saved Regigigas from J who retreated when her client, presumably angry about all the destruction J was causing, cancelled the deal. Regigigas fell asleep again and Brandon promised to protect it, deciding to stay at Snowpoint temple along with Regice, Regirock and Registeel. It is unknown if Brandon caught Regigigas after this event but considering he had already captured three legendary Pokemon it is possible that he did.