Wizard's magic orb becomes more powerful, pop [sic] up to seven Bloons at once.
~ BTD4 Description
Shoots larger and more powerful magical bolts.
~ BTD5 Description
More powerful magic shots move faster and can pop more Bloons.
~ BTD6 description
Intense Magic is the first upgrade on the first path for the Monkey Apprentice. As it says in the description, this upgrade will let the Monkey Apprentice pop 7 bloons and be able to pop frozen bloons. In BTD5, the orbs flash in purple, blue and yellow.