The Onyx-Blade

The Onyx-Blade is a +1 magic item that
deals an additional 1d4 fire damage
As a bonus action, you can change the
properties of The Onyx-Blade, the blade
gain either the versatile, reach, or the
defensive properties for 10 minutes. The
Onyx-Blade can transform 3 times per
day regaining all uses each midnight if
it's outside.