Cheapest priced copy (Strixhaven: School of Mages): $0.35 at Card Kingdom, near mint, their price list as of .
Necrotic Fumes 
Sorcery — Lesson · Uncommon · Strixhaven: School of Mages · #78
As an additional cost to cast this spell, exile a creature you control.
Exile target creature or planeswalker.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Strixhaven: School of Mages | 78 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 16 April 2021Lesson is a spell subtype found on some instant and sorcery cards in the Strixhaven set. The Lesson subtype has no special rules associated with it.
- 16 April 2021Although you may want to include Lessons in your sideboard if you’re playing with cards that instruct you to learn, Lesson cards can be included in your main deck like other instant or sorcery cards.