A Mocker is a dragon-creature shown in the Cave Dragons section of The Incomplete Book of Dragons and nowhere else.
Physical Description
Based on the sole image of the Mocker, they appear to be a small creature, possibly luminescent, with one pair of wings. It bears a slight resemblance to a Slugbulb.
Appearances
The Incomplete Book of Dragons
The Mocker appears only in an image of Cave Dragons in this reference book.