Kentaro, the Smiling Cat [Betrayers of Kamigawa]

Description

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
You may pay {X} rather than pay the mana cost for Samurai spells you cast, where X is that spell’s mana value.”The bonds of bushido will draw the dishonored back someday, and I will be there waiting.”