Dark Simulacrum

[Shiira]

You are quite horrible there is nothing in the description that complete binds it to offensive spell use

http://db.mmo-champion.com/s/77606/dark-simulacrum/

"siphoning the magical energies from the enemy's next offensive targeted spell"

[Zerioc]

Also, since I know it came up a couple times early on, it looks like DSi will "store" the spell for up to 20 seconds and allow you to cast it whenever you choose in that time

http://db.mmo-champion.com/s/77616/dark-simulacrum/

( Someone on EJ found that. Not me. )