This is a mini version of the 9-inch-tall Moai Max, that is a little over half as tall, about 5 inches in height. It was part of a wider release of this design.
From Max's South Seas Hideaway:
"Designed by our in-house ceramics team, this mug design is based on a wood carving found inside Max’s. We call this homage to the stone carvings found on Easter Island 'Moai Max.' We created three glaze colors: Sandstone (limited edition of 25), Granite (limited edition of 25), and Volcanic Ash (edition of 50).
The volcanic ash Moai mugs will not be sold online - they’re for in-house sale at Max’s only starting Tuesday, May 31.
All mugs are numbered on the bottom. They hold 14 oz of liquid and stand approximately 9 inches tall.
The Volcanic Ash Moai comes with a little 'mini Moai' sidekick."