Today I had some help from the wonderful Squigglicious and reluctant Mrcoffee in obtaining the (severely underestimated) spell Voracious Trunk, as well as Frost Breath and Lowing >.>. I was anxious to get this spell because it would cut my auto-refresh from 14 points to 11 points which saves me some space for other spells...but little did I know that it actually had some rather interesting uses. I was really bored afterwards (Squig Teleported me to Dem from Uleguerand Range) so I went to Valkurm Dunes and got a crab to use Scissor Guard and then absorbed it with Voracious Trunk. To my utter AMAZEMENT the spell DOUBLED my total defense, it was crazy! So after this I walked around and tested out a few monster abilities that you can absorb via Voracious Trunk (there seems to be absolutely NO info on these abilities for some reason).
Voracious Trunkable Monster Abilities
Scissor Guard - 100% Def increase
Berserk - 50% Attack increase, 50% Def decrease
Water Wall - 100% Def increase
Warcry - 26.25% Attack increase
Arm Block - 25% Def increase
Regeneration - Regens 5 HP per tick
This is obviously far from a complete list, but it makes a nice start. Some abilities you will notice are far greater than their PC job counterparts (Warcry is only 5.25% for WARs but is 26.25% when absorbed from an enemy).