On *:INVITE:#:{
  If ($me == bigbot) {
    Set %invitechan $chan
    If (%invites == $null) { join %invitechan | inc %invites | halt }
    Elseif (%invites == 1) { msg [ba]bigbot join %invitechan | unset %invitechan | unset %invites }
  }
}

On *:TEXT:join *:?:{
  If ($me == [ba]bigbot) {
    Join $2
  }
}