Any way to disable custom text formatting?

[mattspeppers]

Is there any way to disable custom text formatting in comments for all users on my end?  
 
There's one recent user in particular that has made his text about 5 times larger than normal and comments INCESSANTLY.  
 
Please tell me there's a way to disable it. 
 
It's driving me crazy!
 
 
 
         

 

[The Hot Pepper]

No

 

[mattspeppers]

That's unfortunate.