Oversized Weaponry (3.5e Feat)
From D&D Wiki
Oversized Weaponry [General, Fighter]
You can use weapons that are two sizes too big.
Prerequisite: Str 19, Monkey Grip, Gigantic Weapon
Benefit: You can use one-handed weapons that are designed for creatures two size categories bigger then you as a two handed weapon at a -2 penalty.
Normal: Normally you can only wield weapons of your size.
Special: Fighters may choose this feat as a bonus feat.