Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
When Overcharged Amalgam exploits a creature, counter target spell, activated ability, or triggered ability.
As 'Revenge' allready promoted this card;
Overcharged Amalgam is an really good example of a counter spell. Zombie Tribal is a very strong one.. And not everyone of them can fly, true. But the real thing, I would like to point out is 'Exploit'. It might suggest you a disadvantage, but read carefully:
If it enters "you may" sacrafice. This spell is not only a "dead card" when you have nothing to counter. This spell is a counterspell, who can sacrificed itself, if you have no other targets, or that can synergize with many other creatures who wants to get sacrificed. Like 'Biolume Egg', just to name one card that is with overcharged amalgam standard legal atm.
I wouldn't call it a bomb. But this is synergy power at high level.