Jinxed Choker

At the beginning of your end step, target opponent gains control of this artifact and puts a charge counter on it. At the beginning of your upkeep, this artifact deals damage to you equal to the number of charge counters on it. {3}: Put a charge counter on this artifact or remove one from it.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6ohmiycoa1pb1hn2j6j1ml.