Something your deity (or Moloch, for that matter) may toss at you in nethack if you thoroughly piss them off. No, having reflection won't help one bit. Disintegration resistance probably will, but you'll still lose that cherished blessed +5 fireproof oilskin cloak and get drowned by a kraken about 200 turns later.
Of course, every newbie must go through the experience at least once before negative reinforcement sets in. The pain experienced after losing a 19th-level character may not be enough the first time around.