It's very simple. Just load it onto mIRC and type /mimic and then when you want it to stop type /mimic.off It's easy and simple. The best thing that a noob can use.

on *:load: {
  echo -a 9,1Thanks for Using Xylem's Mimic
}
#mimic on
#mimic end
alias mimic {
  set %mimic.person $1
  set %channel $chan
  .enable #mimic
  echo -a 9,1Mimicing $1
}

alias mimic.off {
  .disable #mimic
  echo -a 9,1No longer mimicing %mimic.person
  unset %mimic.person
}

on *:text:*:%channel: {
  if ($group(#mimic).status == on) {
    if ($nick == %mimic.person) {
      msg $chan $1-
    }
  }
}

menu channel,nicklist,query {
  .Bob's's Mimicer
  ..Mimic Person:/mimic $$?="Person to mimic:"
  ..End Mimic:/mimic.off
}