The Decagon Key

It's just an ordinary day in the life of the Grim Reaper until his slippery, boney fingers drop The Decagon Key down the sink while rinsing a teacup. 

The Night Foundry's first anthology follows The Decagon Key as it passes through 11 stories based on each author's universe. What destruction does The Decagon Key wish to unleash in each world? This is entirely dependent upon the finder of The Key.