Boy in the Ice

Boy in the Ice enters the battlefield with 5 frozen counters on it.
At the start of each player's upkeep, remove a
frozen counter from Boy in the Ice.
{t},{1}, if Boy in the Ice has no frozen counters on
it, sacrifice Boy in the Ice: Search your library for
a white Avatar spell with a cultivated mana cost
of 4 or less and put it onto the battlefield.