Spread unending torment and darkness!
Henzell says...
  1. Every time a monster makes a movement (i.e. not an attack/spell), the amount of time taken to do its turn has a 1/3 chance of being 0.1 turns slower, a 1/3 chance of being 0.1 turns quicker and a 1/3 chance of being the normal amount. Over time, these 0.1s add up or cancel out to cause 'double moves' or 'lost moves'. Replaced with {attack of opportunity} in 0.29.
  2. The purpose of this feature is to make pillar dancing more unpredictable. When a monster gains/loses a move is when it is most likely to lose/gain it again. The worst case for a 1.0 move delay monster and player is a double move every 10 turns.
  3. You can still dance nearly as easily with anything other than a pillar.

Information based on master branch and the great LearnDB.
© Dungeon Crawl Stone Soup, 2010.