The Monkey's Paw, a classic tale of horror and superstition, a much anthologized short story by W.W. Jacobs, published in 1902 in the collection "The Lady of the Barge." The story centers on a dried, shrunken monkey's paw that is said to have the power to grant its possessor three wishes.
Just in Alchemy there is a system of checks and balances and if you choose to tip the scales; you can lose something of greater value than what is gained.
"Equal" Exchange.
Don't tempt fate, and be careful what you wish for... you just might get it.