Invisibility

Ranged spell
Daily
Target: 
You or one nearby ally
Effect: 

Until the end of the battle (or for five minutes out of combat), the target becomes invisible until it attacks or uses some ridiculously flashy action.

High Arcana: The duration out of combat is 1 hour instead.

7th Level Spell: 
You can now target 1d3 nearby allies (including you) with the spell.
9th Level Spell: 
Creatures made invisible by the spell have a 25% chance of remaining invisible the first time (and first time only) they attack or get flashy.