Elder Sign token
From Arkham Horror Wiki
The Elder Sign token is the converse side of the Doom token.
On sealing a gate, an Elder Sign token is placed on the location to indicate that a gate can no longer open at that location.
When the gate is sealed by using the Elder Sign unique item, a Doom token is taken from the Ancient One's Doom track and flipped over to place on the location. If the gate is sealed using clue tokens, or as the effect of a Mythos or Encounter card, the token is taken from the pool of unused doom tokens.
