Server 1.3.0 off of CVS... The cause light wounds spell can make monsters invulverable. This has happened to me repeatedly. No (reasonable amount of) damage can kill the creature after this happens... If I were to guess, I'd guess that the death check isn't working quite right... This character I see this with at the moment is a lvl 2 wisdom character with 5 Grace. He's level 8 physical and cannot kill this particular gnoll with hundreds of successful hits with any melee weapon - even one that does damage other than physical. So, then if I let the invulnerable gnoll get out of the way I am firing, I can kill other gnolls with cause light wounds or waste hordes of them by melee. Every now and then cause light wounds will make another invulnerable. Magic spells never seem to do this...