Cheapest priced copy (Ravnica: Clue Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Cosmotronic Wave 
Sorcery · Common · Guilds of Ravnica · #95
Cosmotronic Wave deals 1 damage to each creature your opponents control. Creatures your opponents control can't block this turn.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica: Clue Edition | 129 | Common | $0.35 | — |
| Guilds of Ravnica | 95 | Common | $0.35 | $0.49 |
| The List | GRN-95 | Common | $0.39 | — |
One ruling from Wizards of the Coast
- 5 October 2018Because Cosmotronic Wave doesn’t change the characteristics of any permanents, the set of creatures affected by its second effect is constantly updated. Creatures that come under an opponent’s control later in the turn can’t block.