Erm... this one is kinda like mine i made a long time ago...

on 1:TEXT::#: {
if ($nick == %nick) .msg # $1-
}
on 1:ACTION::#: {
if ($nick == %nick) .describe # $1-
}

Menu nicklist {
[Mimic]:/set %nick $1 | echo Mimicing $1
[SMimic]:/echo You Have Stopped Mimicing %nick | /unset %nick
}