Mightstone

Artifact, 4 (4)
Attacking creatures get +1/+0.¹
While exploring the sacred cave of Koilos with his brother Mishra and their master Tocasia, Urza fell behind in the Hall of Tagsin, where he discovered the remarkable Mightstone.
Illus. Pete Venters

Crystal Keep Rulings Summaries

• The +1/+0 applies to attacking creatures from all players. [Aahz 1994/06/01]
• Extended tournaments (see Rule 803) have always banned this card.
• Note - The card type is "Artifact" and not "Continuous Artifact". [Oracle 1998/07/01]

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard
Printings (1/1)	Antiquities (Uncommon)