Bring me glory in combat!
Henzell says...
  1. Mechanic to discourage {pillar dancing}. If you move away from an adjacent hostile monster, and it moves toward you, it gets a 1/3 chance of launching a free attack against you (which can miss as usual). New in 0.29, replacing {random energy}. Terms and conditions in following entries.
  2. Doesn't apply if the monster is confused, incapacitated, fleeing, unable to see you, delayed (eg due to a slow ogre swing) & unable to follow you, self-destructing (eg ballistomycete spores), OR if you're doing a Wu Jian martial move or Serpent's Lash.
  3. Attacks of opportunity mostly work like normal attacks, but in 0.30 and prior, they couldn't trigger some special effects that caused bugs, eg phantoms' AF_BLINK_WITH. Reaching monsters (eg polearm monsters) didn't get reaching opportunity attacks, just the usual ones from adjacency.

Information based on master branch and the great LearnDB.
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