A figurine of wondrous power is a statuette of a beast small enough to fit in a pocket. If you use an action to speak the command word and throw the figurine to a point on the ground within 60 feet of you, the figurine becomes a living creature. If the space where the creature would appear is occupied by other creatures or objects, or if there isn't enough space for the creature, the figurine doesn't become a creature.

The creature is friendly to you and your companions. It understands your languages and obeys your spoken commands. If you issue no commands, the creature defends itself but takes no other actions.

The creature exists for a duration specific to each figurine. At the end of the duration, the creature reverts to its figurine form. It reverts to a figurine early if it drops to 0 hit points or if you use an action to speak the command word again while touching it. When the creature becomes a figurine again, its property can't be used again until a certain amount of time has passed, as specified in the figurine's description.

Adamantine Tarrasque (Artifact). This adamantine statuette depicts a titanic monstrosity roaring amidst the rubble of a destroyed building.  It can become a tarrasque for 10 minutes. Once it has been used, it can't be used again until 30 days have passed.

The figurine requires concentration to control.  The Constitution saving throw to maintain concentration on the figurine uses a DC of 20 instead of 10, and must be repeated at the end of each of your turns in addition to any other time you would be required to make a concentration check.  If your concentration is broken, you lose control of the figurine and it becomes hostile towards all creatures, objects, and structures for the remainder of its duration.

Notes: Summoning