A comeback used when people that think of themselves as popular or cool make a lame one-liner and think it's the funniest thing since "I'm on a boat," when in reality you aren't affected at all.
Derived from those teen movies in the 80's when the bitch and her best friend/follower make a cheesy remark, usually followed by a high-five, or something of its equivalent.
New Girl: Who are they?
Friend: They're the most popular girls in school... Oh crap, they're coming this way! Quick, look away!
Popular Girl #1: What are you looking at geekface?
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2 million.