4% chance if there is any attack, leap, or pit shove
The prior change made it too easy for the elf to safely shoot from next to a pit. So, we made this change:
At the end of any round in which there was an attack (any attack roll), a non-magical leap, or a monster shoved into a pit, there is a 4% chance of attracting a purple worm. (Unless all worms are dead.)
At the end of the following round, any attracted worm will emerge from a randomly determined pit, weighted towards pits that have more bodies around them. For example, a pit with the hero and one monster adjacent to it would be twice as likely to be the worm’s destination as a pit with just one monster by it. Worms will not emerge from pits with no adjacent target unless it’s the only option.