Oracle Text

Enchantment — Class

(Gain the next level as a sorcery to add its ability.) Spells your opponents cast during your turn cost {1} more to cast. {2}{W}: Level 2 Creatures you control get +1/+1. {4}{W}: Level 3 Whenever you attack, until end of turn, target attacking creature gets +1/+1 for each other attacking creature and gains double strike.