Trenchroller Armor (Patreon)

Armor (half plate or plate), very rare (requires attunement)

This heavy, rounded armor is marked by a glowing crystal at its center. While wearing the armor, you gain a +1 bonus to your AC. As a bonus action, you can transform into a 2-foot-diameter metallic sphere. Your equipment melds into the new form. While transformed, your size is Small, and opportunity attacks against you are made with disadvantage. Your senses are unaffected while in this form, although you don't need to breathe for the duration. Your AC also remains the same, but you can only take the Dash, Disengage, or Dodge action. You can use a bonus action to take the Dash action while transformed.

You can remain in this form for up to 1 hour, until you drop to 0 hit points, or until you use a bonus action to return to your normal form. Deduct a minimum of 1 minute from the armor's total transformation time each time you transform, even if you aren't transformed for the full minute. The armor regains all of its expended transformation time daily at dawn.

The ruins had crumbled centuries before, its halls now either choked with rubble or flooded by the steady creep of water. Its arcane golems still survived, however, and served their long-dead creators in the eradication of common delvers. But she was far from common.

Gwyn ran through the halls in search of the undiscovered. As she turned a corner, an ancient, stonework fist lurched toward her. Her eyes grew wide in surprise as the crystal in her armor's core began to glow. All at once, her humanoid form retracted inward and rotated into a metal sphere—narrowly dodging the golem's attack. Without a moment to lose, she rolled toward the end of the chamber and away from the golem's reach.

The metal sphere glimmered with crystalline veins, which lent her traction to avoid the onslaught of arcane rays launched from the construct's eye. Reaching the edge of the chamber, she skid to a halt ahead of her massive foe before unfurling into a crouching stance.

With a hunter's calm, Gwyn looked down the sights of her heavy crossbow and took aim at the golem's gleaming eye. As it grew bright to let loose another barrage of deadly beams, her own bolt shattered and pierced it, plunging into the construct's stone frame. The light winked out, and the ancient defender collapsed into rubble—joining the rest of the ruin in eternal rest.