@Dasva: I was under the impression that base Magic Critical is a 10% damage increase, so 1.1x 9853 = 10838 (2 off, probably due to rounding). Not to mention, Enervation is -8MDB, which would not produce such a large damage increase on its own I believe.
Too big of a dmg difference to be a crit unless you rocking a good +80-100ish to crit dmg. Most likely you put magic def down on them and it wore off on some of them.