Sailor Moon Crystal Episode 18 English Dubbed Episode Title:Invasion -Sailor Venus-.Episode Description:Artemis analyzes one of Petz's Malefic Black Crystal earrings, of which Chibiusa is terrified. Rubeus sends the fourth and final Specter Sister, Calaveras. Calaveras uses her medium powers to channel Rubeus and call upon the powers of her fallen sisters by possessing others. While Minako faces Calaveras, Rubeus confronts Usagi and Chibiusa, but they are saved by Mamoru. Calaveras manages to capture Minako, but Usagi defeats her and manages to save Minako. Chibiusa explains that she comes from 30th century Earth to seek Usagi's help in saving her time.