Strength of Ages

Endure (At the beginning of your postcombat main
phase, put an age counter on this permanent, then if
it has three or more age counters on it, add {c}.)
At the beginning of each combat, target creature
you control gets +X/+X until end of turn, where
X is the number of age counters on Strength of
Ages. If that creature has endure, it also gains
indestructible until end of turn.