I believe that you only have to move 1 tile to be able to hit another one. It has happened to me many times now, I hit one (dig again, nothing happens), move 1 tile and hit another one (dig again, nothing happens), move 1 tile etc.... up to 4 times in a row once.
oh, and how far from the portal can it start to spawn?... (I've found ones like... 10 or maybe more tiles away from them)
Last edited by bor45; 10-21-2008 at 02:43 AM.