Another quick shot Ars Magica spell, for almost silencing a group.
Curse of the Bloated Tongues
Rego Corpus 10, R: Touch, D: Dia, T: Group
As per Curse of the Unruly Tongue (ReCo5), modified to target a group, and last diameter. This makes all casting and communications rolls suffer a -6 penalty.
Note: Invented specifically at this level to defend against multiple Magi, and make use of Fidelus’ Flexible Formulaic Magic virtue, to extend the range to Voice when cast. A range Voice version would be level ReCo15.
(Base 2, R: Touch +1, Diameter +1, Group +2)
You can find the rest of the custom spells in the blog’s Ars Magica spell list. Happy gaming.