His name sounds like the basis for a good April fool gag. Everyone knows the Mr C Lion at the zoo ruse, so Juan's, being a bit more subtle, was good.
Try this on some yuppy type in an office.
Leave them a message on their desk, just as they return make out you've just written it before you have to leave, "it's from Mr Gniss, pronounced niss, couldn't quite get his first name, Peter, Paul, Phil, or something. Anyway the initial's P. He said you should ring him urgently about the...(something like Footie tickets or special offer on cosmetics)....."
... then leave the number for the local STD clinic, as they never answer their phone "clap clinic", usually "Lady Joyce Farquar Centre", etc.
Stay just long enough for them to ask for Mr P Gniss.
The more childish the gag, the better the laugh....