Cowbell

Fever (During each opponent's end step you may pay {1} and tap Cowbell. If you do, search your library for
a card named Cowbell.)
At the beginning of your upkeep, if you control
5 or more artifacts named Cowbell, you may create
a colorless artifact token named Gold. It has "Sacrifice this artifact: Add one mana of any color."
A deck may have any number of cards named Cowbell.
"I got a fever; and the only prescription is more cowbell." -Bruce Dickinson