If Cthulhu (Hoary Wings) is in play:

Each investigator at Cthulhu's location discards 1 card at random from hand. Resolve Cthulhu's patrol keyword an additional time.

If Cthulhu (Fierce Visage) is in play:

The investigator with the highest tests (X), where X is Cthulhu's Rage. If they fail, they must either take 1 horror, or choose and discard a non-story asset they control.

If Cthulhu (Wicked Claw) is in play:

If Cthulhu did not move via his patrol keyword this round, Cthulhu (Wicked Claw) attacks each investigator at its location.