As a concept, the idea is quite cool. However, you need to tone the responses down A LOT. Right now this card seems way OP in my opinion. Its not 100% uncounterable, but its getting close...
Mercury tends to be extremely poisonous btw... maybe it should poison the owner every turn as one counter-balance... (in fact, it often acts as a neurotoxin... nudge nudge)
Most of your suggested reactions are nearly hard counters, so they either need to
1) Be removed
2) Be made as a "soft" counter
3) Be limited
4) Have a serious counter balance measure to make a player think twice about using this card.
One other suggestion would be to only allow it to adapt a set number of times in a given player's turn.
One of my favorite pieces of advice I saw from OldTrees was that a player should have to consider whether a card is worth including over other similar cards. If the choice is easy, its probably unbalanced or the player is missing something.