The Sumo Wordman is a pager in Grand Theft Auto III that Claude uses to receive certain missions and messages. It was manufactured by Sumo and it looks to have been made from 1998 to 2001.
The Sumo Wordman will leave a message every time when the player collects 10 per 10 Hidden Packages.
The Sumo Wordman was meant to appear in Grand Theft Auto: Vice City, but cut during development. This is evidenced in the audio files and it is probably replaced by the Mobile Phone, probably a leftover from GTA III.