Absorbs, lightning, weak to holy
I didn't get that information from the bestiary by the way. There's a hacking tool called FF4 SMCHack that I've been using. It lets you edit spells, weapons, armor, items, monsters, monster groups... very useful.
I'm pretty sure this is consistant with all versions, including FF4A. I was confused for a moment though... I'm not familiar with the "Absorbs" flag.
FF2us doesn't have absorb set