Automaton

The Automaton is an ancient humanoid machinery which initially serves as the guardian of the underground entry of the vault of Corona Castle in Tangled: The Series. Varian was able to copy the guardian automaton's design so he could build an army of them, as well as a automaton that he could climb into and control from within.

Lore
While the history of the Guardian Automaton in the Der Sonne's tunnels is unknown, Rapunzel and Varian had encountered it when they used Herz Der Sonne's journal to sneak into the vault of the Castle through the underground tunnel system for stealing the sun-drop flower. In the chamber under the vault, Rapunzel solved the puzzle to open the entry of the vault, but also triggered the switch on the guardian at the same time. Despite its enormous strength, Rapunzel and Varian finally defeated the automaton by strategy. It is believed that Varian had taken its timing cylinder for revesve-engineering before his betrayal to Rapunzel.

In "Secret of the Sun Drop", Varian redesigned the timing cylinder to a music box and sent it with the parts of the automaton as Rapunzel's birthday presents. Rapunzel curiously winded the cylinder with a creepy sound, then the automaton was automatically self-installed. Rapunzel along with Eugene and Cassandra soon encountered the automaton's attack in the Castle. Cassandra found its weakness by stabbing the sword in the timing cylinder and successfully stopped it, but the automation was only Varian's plan of distracting King Frederic.

After Varian had kidnapped Queen Arianna and held her as hostage in his lair, Corona launched the full-out attack on Old Corona with Cassandra's leadership, but they were soon ambushed by an army of automatons mass-produced by Varian. Though the timing cylinders were shielded, Eugene quickly got the idea of using the black rocks to fight against the automatons.

Meanwhile, Varian drove a giant machine altered from automatons to threaten Cassandra and the Queen. Under the awareness of danger, the black rocks converged to Rapunzel and surrounded her. Rapunzel realized her destiny and connection to the rocks, she then successfully controlled the rocks to destroy Varian's giant machine and all the remaining automatons.