Arstron (アーストロン, Aāsutoron), or Earthron is a Kaiju from the Ultraman series. One appeared on his own in RCT3Crashes100's Angry German Kid Series as Tiny Arstron (小型の アーストロン, Kogata Aāsutoron), but it is heavily implied that others exist elsewhere.
Arstron, as Tiny Arstron, first appears in Episode 6, Leopold and the Mysterious Orb. Shortly after Leopold Slikk first transforms into Blue Orb Leopold, a knock at the door triggers him to turn back to normal. Answering the door, he is shocked to find Tiny Arstron there, who despite his name is still 2 metres tall. Tiny Arstron, who had came to the Hotel Adlon after hearing Leopold screaming during the transformation into Blue Orb Leopold, offers him help, in the form of a small Arstron device, which allowed Leopold to restore more HP from the food which he eats. He then warned Leopold of the presence of Palkia in Berlin, and offered to suggest where he should go next. Leopold, happy that he had befriended a Kaiju, thanked Tiny Arstron, and he left the hotel. Tiny Arstron has yet to appear again, but it is likely that he will be helping Leopold Slikk whenever he next appears.
- Arstron is the second Ultraman series character to appear in RCT3Crashes100's Angry German Kid series, after Ultraman Belial, who first appears in the same episode as Arstron.
- Of these characters, Arstron (as Tiny Arstron) is the first of these characters to willingly assist Leopold. Belial planted the Blue Orb in the hopes that it would give him the ability to control Leopold and cause mischief, but he lost control over him, and he didn't do this for Leopold's benefit.