Bulettes are burrowing creatures who attack from underground. Using tremorsense, they leap on unsuspecting travellers from beneath the earth at speed. They have tough hides and a good amount of HP. Because their burrowing is as fast as their normal speed, they make for a relatively dangerous monster. Get this mini for a surprise earthquake-filled attack encounter.
 
Here's a D&D size chart for reference, and if you ever wish to custom print a different size of this design (tiny and small options are not available for printing):
Tiny - 2.5ft x 2.5ft or 1/4 squares x 1/4 squares. Base size ~0.7cm diameter. (eg. most animals)
Small - 5ft x 5ft or 1 square x 1 square.  Base size ~2.5cm diameter. (eg. halflings, dwarves)
Medium - 5ft x 5ft or 1 square x 1 square. Base size ~2.5cm diameter. (eg. most humanoids)
Large - 10ft x 10ft or 2 squares x 2 squares. Base size ~5cm diameter. (eg. trolls, beholders)
Huge - 15ft x 15ft or 3 squares x 3 squares. Base size ~7.7cm diameter. (eg. dinosaurs, giants)
Gargantuan - 20 ft x 20ft or 4 squares x 4 squares. Base size ~10.2 cm diameter. (eg. ancient dragons)