Slicksters who escape drowning will move diagonally through rock. This often results in them "realizing" that they are now in rock and causes them to become confined. This prevents further drowning, but also any movement.
Pictured: One drowning slickster (selected, not confined) having an allowed path go diagonally through rock. One confined slickster (moused over) "created" as a result of a slickster taking such a diagonal path through rock.
Pufts are allowed to move diagonally through rock too, but they somehow avoid confining themselves when not drowning. May be related to drowning state itself?
Have drowning slicksters attempt to escape drowning by going diagonally through solid tiles.