If you control 2 or more Attack Position Spellcaster-Type monsters: Target 1 of them; its ATK becomes 3000 until the end of this turn, but other Spellcaster-Type monsters you control cannot attack this turn.
A monster can have 3000 ATK even if it a low level monster. However it is not easy to have two spellcaster-type monsters on the field since few special summoning spells are playable in the game currently.
In case someone was wondering, for the otk, you can summon protector, then maiden. Use MU on maiden who summon BEWD. Then Synchro with Protector or summon another BE for potential max damage of 11500 damage in 1 turn.