EXCLUSIVE

Kevin Garnett would've laid the smack down on Carmelo Anthony if things came to blows during their post-game standoff this week ... all because of KG's cartoonishly long arms ... so says Marlon Wayans.

Marlon was out in NYC yesterday when we asked about the Melo vs. KG beef -- and his answer ... is ... hilarious.

The highlights -- KG's got arms like Dhalsim from "Street Fighter" ... and on a completely unrelated note, the world is run by vagina. Must watch.