FOILCheapest priced copy (Strixhaven: School of Mages): $0.69 at Card Kingdom, near mint, their price list as of .
Strict Proctor 
Creature — Spirit Cleric · 1/3 · Rare · Strixhaven: School of Mages · #33★
Flying
Whenever a permanent entering causes a triggered ability to trigger, counter that ability unless its controller pays {2}.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $0.69 to $2.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Strixhaven: School of Mages Promos | 33p | Rare | $1.29 | $0.79 |
| Strixhaven: School of Mages Promos | 33s | Rare | — | $1.79 |
| Strixhaven: School of Mages | 33 | Rare | $0.69 | $0.79 |
| Strixhaven: School of Mages | 33★ | Rare | — | — |
| Strixhaven: School of Mages | 294 | Rare | $1.49 | $2.49 |
3 rulings from Wizards of the Coast
- 16 April 2021Abilities that trigger when something else causes an ability to trigger will always go on the stack after the ability that caused them to trigger. For example, Strict Proctor’s ability will always resolve before the triggered ability that caused it to trigger does. This is a change from previous rules.
- 16 April 2021Triggered abilities use the word “when,” “whenever,” or “at.” They’re often written as “[Trigger condition], [effect].”
- 16 April 2021Effects that modify how a creature enters the battlefield are not triggered abilities and are not affected by Strict Proctor’s ability. These include (but aren’t limited to) effects that have a permanent enter the battlefield as a copy of another permanent, effects that have a permanent enter with counters, and effects that have a permanent enter tapped.