Inspired by a recent meta question, which I had to write in English for lack of appropriate Latin vocabulary:
A "sockpuppet", on the internet, is an alternate identity someone creates for nefarious purposes. These identities might be used to avoid bans, to affect voting, or to make it look like the "puppetmaster" has more people backing them than they actually do.
The Romans didn't have the internet, of course, but it's easy to imagine a corrupt politician paying a dozen people off the street to give pre-written speeches at a trial. If someone tried this, what would those "proxies" be called?