This card negates the effect of a trap card. Gain 5 stars per level of cancelled trap.
Stiff Crystal is a 2-star boost card that negates the next trap the user lands on. Instead, they receive 5 times the level of the trap in stars.
Strategic Info
Stiff Crystal is an effective counter to trap based strategies, particularly against characters with powerful trap hypers. and like to place their traps on home bases whenever possible to deny normas and afflict opponents with their debuff respectively. Just about any character can do the same with 
Go Away or 
Sky Restaurant 'Pures', so having Stiff Crystal available greatly decreases the chances of the player having a norma denied by a trap card. While it does refund stars when a trap is destroyed, Sky Restaurant 'Pures' is the only card capable of refunding the whole cost of Stiff Crystal. As such, the refund is mostly to make sure that players don't play Stiff Crystal without reason due to the high 20 star cost.
In order for Stiff Crystal to be worth running in the player's deck, there must be trap cards in the game. If none of the player's opponents are playing trap cards, then Stiff Crystal effectively becomes a dead card. Inversely, if they player plans to bring trap cards, they run the risk of negating their own traps. This card has anti-synergy with 
Piggy Bank, so the player may not want to run both cards in their deck.