Ebony fly figurine
This figurine appears to be a miniature statuette of a fly, approximately 1″ long, carved in ebony. When the figurine is tossed down and the correct command word spoken, it transforms into a giant black fly, the size of a horse (with all the statistics of a hippogriff, except that the fly cannot make attacks). The fly obeys and serves its owner; it understands Common, but does not speak.
If the figurine is broken or destroyed in its statuette form, it is forever ruined. All magic is lost, its power departed. If slain in animal form, the figurine simply reverts to a statuette that can be used again at a later time.
The ebony fly figurine can be used three times per week, for up to 12 hours per use. When 12 hours have passed or when the command word is spoken, the ebony fly again becomes a tiny statuette.