Mine

alias gban {
  if (*!*@* iswm $1) var %m = $1
  elseif ($comchan($1,0) > 0) var %m = $address($1,2)
  else {
    .enable #gban
    if ($2) set %gban.reason $2-
    userhost $1
    halt
  }
  var %a = $chan(0), %b = 1
  while (%b <= %a) {
    var %c = $chan(%b)
    if ($nick(%c,$me,ho)) {
      msg %c 3~2*4»12 Globally banning $qt(%m) $iif($2,for reason: 5 $+ $2-) 4«2*3~
      mode %c +b %m
    }
    inc %b
  }
}
#gban off
raw 302:*:{
  if (!$2) {
    echo 4 -a * /gban: no such nick
  }
  else {
    var %m = $+(*!*@,$gettok($2,2,$asc(@)))
    var %a = $chan(0), %b = 1
    while (%b <= %a) {
      var %c = $chan(%b)
      if ($nick(%c,$me,ho)) {
        msg %c 3~2*4»12 Globally banning $qt(%m) $iif($2,for reason: 5 $+ $2-) 4«2*3~
        mode %c +b %m
      }
      inc %b
    }
  }
  if (%gban.reason) unset %gban.reason
  .disable #gban
}
#gban end