Chunker120 is a player who's highest stat is level 70 in Woodcutting as of 26 May 2011.
He got the idea for his name after he took a huge dump and heard about spelunkers on the News Radio. Chunk (of poo) + spelunker = Chunker
He got the 120 from wanting to achieve 120 Dungeoneering.
Chunker + 120 = Chunker120