The Thief bonus round rule is one of the many rules that can be applied during the Bonus Round episodes, offered only if playing as the Thief. It has a chance to spawn on floors 2 and 3, but is more likely on floor 2.

The Thief

Switch to “Finders Keepers” rules.

When the rule activates, the Thief's stolen card is replaced by the Finders Keepers skillcard. After filling a countdown of 12 and winning the fight, the player will be able to choose a piece of equipment to keep from the enemy.

On the other hand, while this rule is active, all chests are removed from the dungeon (except for the Wooden Stake chest if the boss is Drake). You will have to get all of your equipment from enemies, shops, and the trading post.

This rule is still in effect if you use the Bear Potion and become a bear, so you can still steal a lot of equipment from enemies. However, since chests are still removed, the use of the Bear Potion ultimately only changes the base equipment and level up rewards while disabling shops and trading posts.