Barn is a term used by collectible card gamers. It is short for barnacle. A barn is someone that latches on to someone they admire or aspire to be like. The alpha male/female (hull) in any group will have many barns. The barns will flatter their hull and do their hull's bidding.
"Ever since I won cash on the Magic Pro Tour, I have infy barns"
"These barns are latching on to the stevedore of my success"
"I got this super rare card for free from one of my barns."