ID:157808
 
I want to be able to make water pokemon be able to swim, and fire pokemon walk on lava, flying fly above caves, rock walk on caves, etc. The only thing is, I can't just change the pokemon density, because then a rock pokemon will be able to walk on water, too...

Is there a way to change a turfs density for only one person?
You would override Enter() to allow entry for the appropriate mobs:

turf
water
Enter(var/mob/M)
if(M can swim)
return ..()
else
return 0
I found out right before you replied XD