Cheapest priced copy (Mystery Booster 2): $0.35 at Card Kingdom, near mint, their price list as of .
Tendrils of Agony 
Sorcery · Uncommon · Scourge · #75
Target player loses 2 life and you gain 2 life.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
8 printings · $0.35 to $49.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Friday Night Magic 2008 | 4 | Rare | — | $5.49 |
| Mystery Booster 2 | 50 | Uncommon | $0.35 | — |
| Eternal Weekend | 2025a | Rare | — | — |
| Scourge | 75 | Uncommon | $0.79 | $49.99 |
| Secret Lair Drop | 2004 | Rare | $2.29 | $2.29 |
| Secret Lair Drop | 2023 | Rare | $0.79 | $1.79 |
| Strixhaven Mystical Archive | 34 | Rare | $0.79 | $3.99 |
| Strixhaven Mystical Archive | 97 | Rare | $4.49 | $5.99 |
5 rulings from Wizards of the Coast
- 8 December 2022The copies are put directly onto the stack. They aren't cast and won't be counted by other spells with storm cast later in the turn.
- 8 December 2022The triggered ability that creates the copies can itself be countered by anything that can counter a triggered ability. If it is countered, no copies will be put onto the stack.
- 8 December 2022Spells cast from zones other than a player's hand and spells that were countered are counted by the storm ability.
- 8 December 2022You may choose new targets for any of the copies. You can make different choices for each copy.
- 8 December 2022A copy of a spell can be countered like any other spell, but it must be countered individually. Countering a spell with storm won't affect the copies.