Boros Fury-Shield

Instant, 2W (3)
Prevent all combat damage that would be dealt by target attacking or blocking creature this turn. If {R} was spent to play Boros Fury-Shield, it deals damage to that creature's controller equal to the creature's power.
Illus. Wayne England

Crystal Keep Rulings Summaries

• The second sentence means that you may pay {R} in addition to the casting cost when playing the spell. [D'Angelo 2005/10/04]

Format Legality	Legal in Vintage, Legacy, Extended Banned in Standard
Printings (1/9)	Ravnica: City of Guilds (Common)