Seems Kind of like a single targeting SoP, I like it!
Just a couple questions:
What happens when it get stolen, does you opponent need to target a new creature? or will the effects still apply to the old creature? Also does the effect stack if you target the same creature multiple times? What happens when reverse time is applied to the creature or the creature is killed, will the card be destroyed as well?
What happens when the creature become immaterial, will the effect still work, since it was targeted earlier or will it this card be destroyed?