Spark Rupture

While Spark Rupture is on the battlefield, planeswalkers will enter the battlefield as creatures, but with the appropriate number of loyalty counters. For example, a planeswalker that normally enters with three loyalty counters on it will enter as a 3/3 creature and have three loyalty counters on it.

A planeswalker that becomes a creature due to Spark Rupture is no longer a planeswalker. It can no longer be attacked, and damage dealt to it won't cause it to lose loyalty counters.

If a planeswalker-turned-creature has all loyalty counters removed from it, Spark Rupture's effect will stop applying to it. It will momentarily return to being a planeswalker, but as it has no loyalty counters, it will soon find itself in the graveyard. If this happens, you won't have priority to activate any of its loyalty abilities before the planeswalker is put into its owner's graveyard.