Cheapest priced copy (Dissension): $0.99 at Card Kingdom, near mint, their price list as of .
Pain Magnification 
Enchantment · Uncommon · Dissension · #121
Whenever an opponent is dealt 3 or more damage by a single source, that player discards a card.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.99 to $6.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dissension | 121 | Uncommon | $0.99 | $6.99 |
| The List | DIS-121 | Uncommon | $1.29 | — |
2 rulings from Wizards of the Coast
- 1 May 2006If a source deals 3 or more damage to multiple opponents at the same time, this ability will trigger once for each of those opponents. They will each have to discard a card.
- 1 May 2006This triggers only if all 3 or more damage is dealt at the same time. It doesn’t trigger if damage that adds up to 3 or more is dealt at different times by the same source.