Just right click on a nick and it will work.
Took me all of 50 seconds to make.
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
}