The Pacer Test

Cumulative upkeep {1}
At the beginning of your upkeep, exile all
permanents with converted mana cost less
than or equal to the number of age counters
on The Pacer Test. Return them to the
battlefield under their owners' control when
The Pacer Test leaves the battlefield.
"The FitnessGram Pacer Test is a multi-stage
aerobic capacity test..."