Dragon Quest Monsters: Joker
Behemoth Slimes are valued for being needed in several special synthesis combinations.
Behemoth Slimes appear on an uncharted slime island, and are un-synthesiseable.
Dragon Quest Monsters: Joker 2
Behemoth Slimes are a type of Rank D slime that has several synthesis combinations.
Behemoth Slimes can be found in the Dark World (Dragon Quest).