Loremaster’s Sagacity

Endure (At the beginning of your postcombat main
phase, put an endurance counter on this permanent,
then if it has three or more on it, add {c}.)
At the beginning of your end step, you may cast
a noncreature spell from your hand with mana
value X or less, where X is the number of
endurance counters on Loremaster`s Sagacity
without paying its mana cost.