Preston Lacy -- the guy who farted into the fart mask in "Jackass 3D" -- was arrested earlier this month after cops discovered something else with potent fumes ... marijuana.
TMZ has learned ... Lacy was busted in Oklahoma on December 14 -- after cops say Lacy was in possession of a controlled substance (weed) and drug paraphernalia (rolling papers).
Lacy was charged with two misdemeanors -- and if convicted, he could spend up to two years in prison and face $2,000 in fines.
Attempts to reach Preston were unsuccessful.
Waiting for your permission to load the comments.