Darkubes

The Darkubes are a swarm of Emblem Heartless that appear in Kingdom Hearts III.

Kingdom Hearts III
The Darkubes are released on San Fransokyo by Dark Riku in an experiment to create a complete heart from data, using the first combat chip that Hiro Hamada created for Baymax. They are encountered by Sora, Donald, Goofy, and the members of Big Hero 6 after a day spent successfully fighting the Heartless attacking the city, and given their moniker by Fred. After an unsuccessful attempt at fighting the Darkubes, Sora, Donald, and Goofy work to free Wasabi, Go Go Tomago, Honey Lemon, and Fred, who have been incapacitated by Darkubes.

During this time, Hiro determines that the Darkubes operate from a central core located at a high vantage point. When Sora, Donald, Goofy, and Big Hero 6 go to confront the Darkubes, they meet Dark Riku, who is observing the data stored on the combat chip. He then sets the Darkubes on Sora and his friends; although the Heartless is defeated, Dark Riku reclaims the combat chip and withdraws.

A new set of Darkubes attack San Fransokyo again the next day. This time, however, Dark Riku destroys the core before the Heartless can face Sora and his friends, having determined that the combat chip contains the data he needs. The leftover Darkubes are then used by Dark Riku to pull the original Baymax out of the other dimension; the Darkubes fuse into a copy of the combat armor, creating Dark Baymax.

Following the defeat of Dark Baymax and the destruction of his dark combat chip, the Darkubes completely vanish.

Design
The central core Heartless of the Darkubes is a cubical Heartless that is surrounded by cubes glowing red. Its body is black, with Heartless-characteristic glowing yellow eyes. The Darkubes themselves are black cubes covered with patterns identical to those of the Blox. They glow white when idle, and red when preparing to attack.

Being artificial like the Experiment, the Darkubes do not follow basic Heartless behavior. Unlike it, the Darkubes can be mass-produced easily due to their simple design; Dark Riku was able to summon another set of Darkubes the following day.

While not possessing a traditional emblem like most Emblem Heartless, when idle, the Darkubes gather in the shape of a heart.

The Darkubes are based on the Microbots created by Hiro Hamada in the 2014 Disney animated film Big Hero 6, and briefly mistaken for such by Hiro in Kingdom Hearts III.

Strategy
After its attacks, the Darkubes' core will occasionally be vulnerable. When the core is not vulnerable, focus on defense. Wearing Dark-resistant armor will prove useful, as all of its attacks deal Dark damage.