Absorbed the Sharp Spike effect from Hedjetjet last night, no clue how much the atk+ was, but I went from doing 1.5k Cata's to 2.8k AVG with it up. It lasted for 18 minutes... I was freaking out lol.
Edit: The only thing I've ever been able to absorb from carabosse is shell, regain, and regen. The regain is 10/tick though which is pretty stellar. Lasts a few mins, 3-5~ from what I can tell.