All or Nothing Coin

This item appears as a gold coin with an emerald embedded in its center, suspended in mid-air inside a glass case. Once a day, before any ability check, flip the coin. Player can use any 50/50 odds method of rolling to do this (flip a coin, odds or evens, etc). If the player is correct in their call, the coin renders the ability check an instant critical success. If the player is wrong, it is an instant critical failure.