Talk:Improved Invisibility/@comment-2.10.128.52-20181017122601/@comment-2.10.128.52-20181020011749

Note that there *is* an invisibility spell that grants a +4 saving throw bonus: Mass Invisibility. It's cumulative too, so beware the cheese, because casting it twice means +8 bonus, at which point you're edging on immunity against anything that allows a save.

No other invisibility spell grants this saving throw bonus because it is granted separately from the invisility status by Mass Invisibility only. So not Improved invisibility, not Mislead, not Shadow Door, nothing but Mass Invis.