Zem, brother of ice

Zem enters the battlefield with X charge counters
{t}{x}: add X charge counters to Zem
{t}: remove any number of charge counters
and triger effect acording to the number of
charges removed:
1: draw a card, search in your libary for the
"Ice shield, of lost mind"
2: counter target spell wtith converted mana
cost 2 or less
3: exile target creature