Regeneration cannot save a creature with zero toughness.

Regeneration prevents a creature from being destroyed. Destruction is caused by effects that specifically use the word ‘destroy’ or when a creature receives damage equal to its toughness. Effects that lower a creature’s toughness to zero or below will not cause destruction. Because of this regeneration will not save a creature that has a toughness […]

Read more.

When does Argent Sphinx come back into the battlefield?

When ’s activated ability resolves the Sphinx is exiled and a delayed triggered ability is put on the stack. This trigger will wait around until the next end of turn step begins. If this ability is activated in an end of turn step, then the Sphinx will not return to play until the next end […]

Read more.

How Vigilance works:

Vigilance is a static ability that affects creatures when they are declared as attackers. Creatures with vigilance do not become tapped when they are declared as attacking. This does not mean that tapped creatures can attack. Also, removing vigilance from an attacking creature will not cause it to be come tapped.

Read more.