What about ^#%& as was traditional in newspaper comics strips?
How about "Pockmark!... Freshwater swabs!... Bully!.." or "Amoeba! Bashi-bazouks! Chowderheads! Certified Diplodocuses! Nyctalop! Ectoplasm!"?
Known as grawlix or obscenicon.
https://en.wikipedia.org/wiki/Grawlix
alt Hacker News
How about "Pockmark!... Freshwater swabs!... Bully!.." or "Amoeba! Bashi-bazouks! Chowderheads! Certified Diplodocuses! Nyctalop! Ectoplasm!"?