From Arkham Horror Wiki
The Innsmouth Plague is a mythos card. It first appeared in the Innsmouth Horror expansion.
Mythos Type: Rumor
Doom Tokens Added: 2
Clue Appears At: -None-
Mythos Ability: Ongoing Effect: At the end of every Mythos Phase (beginning the turn after this card enters play), the first player draws one Innsmouth Look card.
Pass: If an investigator discards 2 Spells during the Arkham Encounters Phase while in the Church Green streets, return this card to the box.
Fail: If an investigator gets the Innsmouth Look and is devoured, return this card to the box.
Flavor Text: A terrible plague begins to spread from the city of Innsmouth.