An idiom used to describe the moment of downturn for a previously successful enterprise/musician/actor etc. A clear, defining point which, when reached, means nothing will be the same again.
Similar to 'Jumping the Shark' or 'Nuking the Fridge'.
From LoudReed and his wife staging a high frequency dog concert ("an inter-species social gathering").....
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.