Minecraft Dungeons:Banner

The Banner is a consumable item dropped by Raid Captains where upon obtaining, grants the level enhanced modifiers which make the level harder to finish.

Obtaining
Banners can be obtained from slaying a Raid Captain and can drop either a Bad Omen or a Mystery banner.

Usage
Upon being obtained, enhanced modifiers will be added to the level which make the level more difficult, such as enemies getting enchanted or mobs being replaced with powerful mobs.