Vanilla Mass Invisibility

Mass Invisibility
(Illusion/Phantasm)

Level: 7
Range: Visual range of the caster
Duration: 1 round/level
Casting Time: 7
Area of Effect: 15-ft. radius
Saving Throw: None

Upon casting this spell, the wizard causes all friendly creatures within the area of effect to be affected by the spell Improved Invisibility. This spell is similar to the Invisibility spell, but the recipient is able to attack, either by missile discharge, melee combat, or spellcasting, and remain unseen. Note, however, that there are sometimes telltale traces, a shimmering, so that an observant opponent can attack the invisible spell recipient. These traces are only noticeable when specifically looked for (after the invisible character has made <PRO_HISHER> presence known). Attacks against the invisible character suffer -4 penalties to the attack rolls, and the invisible character’s Saving Throws are made with a +4 bonus.