Munchlax is a Pokemon that was introduced in Generation IV (Diamond, Pearl, Platinum, Heart Gold, and Soul Silver). It is a Normal type that evolves into Snorlax with high happiness which evolves into Skylax with a Sun Stone.
The Munchlax that is traded to you is holding a Sun Stone. It also appears to always have an Adamant nature and 31 IVs in every stat.
- Trade Faceleech for it in Slateport City.