Aether Serpent

Hidden(the enemy player does not know this card is on the battlefield until you attack with it)
When Aether Serpent enters the battlefield,
you get X Energy Counters
{t}{e} transform Aether Serpent.(see Aether Amulet)
{t}{e}{e} Put one +1/+1 counter on Aether Serpent
{e}{e}{e}{e} Aether Serpent Cannot be blocked until
end of turn
"Said to have been invented by Tezzeret himself as an assassination tool"