Mystery of the Planeswalker

Whenever a planeswalker you control activates a loyalty counter, double the number of counters placed on it.
{1}{w}: Reveal the top three cards of your library and put any number of those cards in your hand. For each card put in your hand this way, target planeswalker you control loses that many loyalty counters. Otherwise, put those cards on
the bottom of your library.(Activate this ability only once per turn.)