I was intrigued with the card and have used it for every sphere so far on many main and obscure units....here's my results.
Dragonrider/ Wasseir- Quite effective for his hit all units skill, but really just a tankie afel. I did love pulling it off though
Stardragon: It's decent, but with salamanders being played, makes it hard to keep dragon on field alone since HP buff is more important.
Brutal Mammoth: Effective if you can get some defense on him afterward.
Veteran Folrart Paladin: OMG this was awesome.
Star Lord / Bastandorra: Decent as it gives him 60 attack
Zu: This was great, but need overdose to force kills sometimes.
Death Knight: This was sick with lich in back
Crest Devil Knight: Depends on rivals field, but he can virtually fully heal every turn at 100 HP
Last Resort / Gaieshart: If you can time it after he gets an AT buff first. Pure evil
Living Armor: Can we say ultimate tank
Earth Dragon: Drool
Giant Arthropleurid: Helps for resting and waiting for DEF to build.
Volcano Wyvern and Bringer: Did it for giggles. Bringer was hardcore.
Giant Manta Ray: Worked very well
Mage Paladin / Distrier: If you have sp to follow up with AT and DEF boost. Slaughter
Giant Ancient Tortoise: This was totally awesome.
Deep Squid: Well think of dalos with guaranteed 80 damage.