Someone

alias rainnick {
  set %RainbowChan #
  set %RainbowColors 4,7,8,9,11,12,6
  set %RainbowColorVar 1
  set %RainbowNickVar 1
  set %RainStatus Off
  timerRainNick -m 0 10 RainNickGo
}

alias -l RainNickGo {
  :RainStart
  if (%RainbowColorVar > 7) {
    set %RainbowColorVar 1
    goto RainStart
    halt
  }
  elseif (%RainbowNickVar > $nick(%RainbowChan,0)) {
    set %RainbowNickVar 1
    goto RainStart
    halt
  }
  var %RainbowColor = $gettok(%RainbowColors,%RainbowColorVar,44)
  cline %RainbowColor %RainbowChan $nick(%RainbowChan,%RainbowNickVar)
  inc %RainbowNickVar
  inc %RainbowColorVar
}

alias rainoff {
  timerRainNick off
  unset %RainbowChan
  unset %RainbowColors
  unset %RainbowColorVar
  unset %RainbowNickVar
  set %RainStatus On
  var %i 0
  while %i < $line(#,0,1) {
    inc %i
    cline -r # %i
  }
}

menu channel {
  -
  Rainbow Nicklist %RainStatus:{
    if (%RainStatus == Off) {
      rainoff
    }
    else {
      rainnick
    }
  }
  -
}