Cheapest priced copy (Double Masters): $0.49 at Card Kingdom, near mint, their price list as of .
Magus of the Abyss 
Creature — Human Wizard · 4/3 · Rare · Future Sight · #70
At the beginning of each player's upkeep, destroy target nonartifact creature that player controls of their choice. It can't be regenerated.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $0.49 to $1.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters | 97 | Rare | $0.49 | $0.49 |
| Commander 2017 | 115 | Rare | $0.49 | — |
| Future Sight | 70 | Rare | $0.69 | $1.99 |
2 rulings from Wizards of the Coast
- 7 August 2020The triggered ability can target a creature with indestructible. It won't be destroyed.
- 7 August 2020Even though the player whose upkeep it is chooses the target creature, you control the ability. An opponent can't target a creature with hexproof they control.