School Me Once...

 is a Defense Perk that can be equipped in MultiVersus.

How to Unlock

 * For Iron Giant: Reach Mastery Level 7.
 * For Taz: Reach Mastery Level 11.
 * For Tom & Jerry: Reach Mastery Level 13.
 * For other Fighters: via Perk Training.

Solo
Your team receives a projectile block buff for 2 seconds after being knocked back by a projectile.

Stacked
Your team receives a projectile block buff for 4 seconds after being knocked back by a projectile.

Trivia

 * This Perk was originally known as Projectile Block.