Nightmare State Indicator are Objects, Items, Structure and Mobs that changes appearance, color, and behavior during the Nightmare State in a Ruins. Aside form Thulecite Medallion there are many other items that changes color during the Nightmare State. Items, Objects, Mobs, and Structures that are or some part purple or red colored appearance turns into bright pinkish and bright red-orange appearance respectively. Nightmare State Indicator does not apply to Mobs, Objects, and Structure which are not normally can be found in a Ruins.
In this category list all the possible indicators:
“The Slurper is a creature found only in the Ruins, in Wilds and Village biomes. It attacks by...Slurper