AC Valhalla's mushroom gates are at the center of the Fly Agaric Norway Mystery. These gates, found on the island of Rygafylke, only appear once the player has ingested the hallucinogenic mushrooms found in the middle of a ring of stones, by three statues of Norse gods. A note on by the statues gives a hint as to the order in which to enter these gates, but the instructions could stand to be a little clearer. Here's how to solve the mushroom gates puzzle.
AC Valhalla Mushroom Gates: How to Solve the Puzzle
The solution to this Assassin's Creed Valhalla puzzle is very simple if a little unclear. After eating the mushrooms in the ring of stones, three gates will appear around the player. Turn to face the statues that held the note, then run through the gate to your right. This is the gate to Thruthheim.
Passing through will bring you back to the ring of stones. Turn left from the statues now and pass through the gate to Folkvang. Finally, back at the ring of stones, turn 180 degrees, directly away from the statues, and pass through the gate to Gladsheim. This will complete the mystery.