amplify powers

"The enchanter stops in an act of concentration, in which he slowly and visibly condenses his energies in preparation for casting a spell."

The moment the spellcaster casts this spell he must select another spell from his spell list.
From the moment of casting this spell until he casts a new spell, the caster cannot make use of his action, bonus action, movement speed and reaction except for casting the spell selected.

For each round (including the casting round) spent maintaining concentration on this spell, the selected spell, casted before or within the round following the last round spent in maintaining concentration on this spell, is enhanced by the following effects:

• the damage inflicted by the selected spell adds damage equal to the spell caster proficiency modifier, of the type of the spell, a number of times equal to the rounds (including the casting round) spent maintaining concentration on this spell.
• The hit rolls made by the selected spell add the caster's proficiency modifier a number of times equal to the round (including the casting round) spent maintaining concentration on this spell.
• The saving throws imposed by the selected spell add +2 to the DC a number of times equal to the rounds (including the casting round) spent maintaining concentration on this spell.
• All hit points and temporary hit points gained through the selected spell are increased by an amount equal to the caster's level, this a number of times equal to the rounds (including the casting round) spent maintaining concentration on this spell.
• Bonuses to the C.A. Obtained from the spell, increase by +2 a number of times equal to the turns (including the casting turn) spent maintaining concentration on this spell.