feather star
... that if an arm of a feather star breaks off, then at least two will grow to replace it?
... that if an arm of a <b id="mwDxc"><a href="./Comatulida" id="mwDxg" rel="mw:WikiLink" title="Comatulida">feather star</a></b> <i id="mwDxk">(pictured)</i> breaks off, then at least two will grow to replace it?