You have two extra stats, Strange and Shadow.

Strange is an ability modifier, like Tough or Cool. It starts at +1. This represents your psychic abilities, or space wizardry, or whatever the specifics are for your game.

Shadow is a track with six check boxes. It's the dark side, the cosmic entity inside you, your id unleashed, what have you.

Whenever you make a move, you can choose to roll +Strange instead of the normal modifier. Describe how your strange abilities influence the situation.

On a 6-, in addition to any other consequences, mark a box in your Shadow track. A glimpse of the malevolent force will be seen by those around.

When your Shadow track is full, your character is fully consumed by it and becomes an NPC threat to the setting at large.