if you own the server, you can use a tegular mutator to do that...
remember that the server is in charge, you can't apply (almost) a mutator without having it cleared by the server.
The server decides what mutators to run, and if the client don't have those, it sends them...
Some stuff is runable on client only, like aimbots, but those aren't fair, so thanks to cshp and the like, one can get a fair gameplay without retards.
to make a regular replace-mutator check
this tread