A response used when someone includes you in their plans without asking, to which you would respond if the 'we' they are referring to is them and the rock in their pocket.
"Yeah, we're going to that concert tomorrow night"
"We? What, you got a rock in your pocket? Because I'm certainly not going."
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 $2million.