Resources

Magic: The Gathering Comprehensive Rules Changes

Time Spiral to Planar Chaos (Single Change View)

General changes

Old rule (Time Spiral) New rule (Planar Chaos)

502.60b.

Vanishing without a number means "At the beginning of your upkeep, if this permanent has a time counter on it, remove a time counter from it" and "When the last time counter is removed from this permanent, sacrifice it."