A type of boss in Deltarune. They are optional, often hidden encounters that are more difficult than the rest of the Chapter, but reward the party with powerful exclusive equipment and an instance of the Shadow Crystal (Deltarune) item when completed.
Use this tag when at least three of the bosses are featured in a post. ERAM (Deltarune) may appear in place of the Knight, as their encounter is thematically more similar to the other bosses than the Knight's.