op cannon

(pronounced like the first syllable in 'open') A massive joint, spliff, doobie, blunt, or other, preferably rolled as cone, containing some combination of weed/hash and opium.

"Yo dog, roll up a fat op cannon"

A: "Damn yo, I'm fuckin faded, whats in this?"
B: "Damn straight yo, you're puffin on an op cannon"

A: "wooorrrddd..."