When Hieromancer's Cage enters the battlefield, exile target nonland permanent an opponent controls until Hieromancer's Cage leaves the battlefield.
Auras attached to the exiled permanent will be put into their owners’ graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled permanent will cease to exist.
If Hieromancer’s Cage leaves the battlefield before its triggered ability resolves, the target permanent won’t be exiled.
If a token is exiled this way, it will cease to exist and won’t return to the battlefield.