What about the massacre-style effect of Ascendant Evincar but done differently, taking on his devouring the life essence of those around him for more power to kill opposing creatures
You dont need more than a few in the average goblin deck anyway
While incredibly situational and requiring a lot of mana to be left on the board when you pass the turn, which is sure to raise suspicions with your opponent, if you can pull off this spell at an opportune time when your opponent has used up all their mana, it can be completely demoralizing, effectively making it so they may as well have skipped a turn
Blitz (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.) Whenever this creature attacks, target creature gets +1/+0 until end of turn
Creatures seem to often either have a huge power value or lifelink but rarely both
If they were already attached to other creatures, they remain attached to those creatures