A treasure key being collected.
Treasure keys were a type of loot Sly Cooper had to obtain in Sly Cooper and the Thievius Raccoonus. Each member of the Fiendish Five, excluding Clockwerk, hid these keys in trophy cases throughout the far corners of their respective territories. The keys are light blue with yellow handles and emit a golden glow, which is most prominent when they are collected or used to unlock mechanisms.
Sly typically begins a mission near a hub entrance and must navigate the environment to reach the key. The first key of each world is generally located near the end of the starting area. Keys are earned by reaching the end of a level or as a specific prize. Collecting three to four keys usually grants access to the second half of a hub, while seven keys are required to enter a boss's main quarters.
Additionally, Murray is responsible for obtaining keys in four specific missions. Two of these involve Sly using a blaster to defend Murray as he retrieves a key, while the other two require Murray to win a three-lap race in the team van to earn a key as a prize.