a prank I did in my live sound days was to insert an IPS33 (pitch shifter) into the lead singer's monitor path - set 1/2 step higher. Only did it at soundcheck, but the other band members usually found it hilarious
Bill: I remember an engineer who fed the talkback mic through a PCM 42 on infinite repeats only to the headphones. The producer would talk to the musos and be met with blank stares
12 September at 17:14
Bill: With just the top drawbar pulled out on a B3, play a single note in the top 2 octaves somewhere - fade it up from zero, leslie running in chorale mode, let it hover, then fade out quickly.
Your friendly stage mixer fella will grapple with that for quite a while. It sounds precisely like a microphone on the tipping point of feedback.
12 September at 17:17
Bill: I like the digi pitch plugin. While everyone is coming in to listen to a take, insert Pitch on everything but drums. Randomly set different instruments as much as a 30 cents +/- and adjust the delays.
^This man exists in real life^