The DT-87 Drone is a non-sentient security drone from the 2017 Continuum
The DT-87 Drone is a hovering robot of limited intelligence, which was purchased by Scrooge McDuck in 2018 to guard McDuck Manor against intruders — much to the delight of Webby Vanderquack (who thought its fighting abilities, which included melting through solid steel, absolutely awesome).
On the very day it was installed in the Manor, however, the Drone threatened to disintegrate Dewey Duck, having confused playacting for an actual cry of help from his room. To save him, Webby hijacked the Drone, ripping out wiring to hide inside its casing and control it from within.
This worked as a prank, but when she came out of the shell, the Drone resumed function — only, much, much stupider and more aggressive than it had been previously, because of the damage she had dealt to its processing circuits. Going haywire, the Drone transported Dewey and Webby to Drake Estate, where Webby finally managed to reprogram it to take them (along with Huey and Louie, who had both washed up at Drake Estate on their own) back to the Manor.
Behind the scenes
Like with the DT-87 Security System of McMystery at McDuck McManor, “DT-87” is an allusion to the original 1987 DuckTales series' name. According to Frank Angones, the DT-87 Drone is actually an upgrade of the Security System seen previously, rather than just a namesake.
In December of 2018, the story The Incredible Shrinking Webby introduced a group of sentient robots whose design was inspired by the Drone, the Robotic Antibodies. It is possible that, in-universe, Gyro Gearloose drew inspiration from the Drone when designing them.