Moonclipsa is the ship between Queen Moon and Eclipsa. The ship gained some popularity after "Total Eclipsa the Moon" aired.
In "Moon the Undaunted", when Moon is under the stress of becoming the new queen at a young age, she gets help from Eclipsa to stop the war. Eclipsa sympathizes with Moon since her mother died when she was young as well. She tells Moon how to use her darkest spell to kill Toffee.
In "Stranger Danger", Moon believes Eclipsa is evil after the dark magic started spreading on her arms and tries to crystalize Eclipsa again with the High Commission, but Star convinces Moon to hold a trial.
In "Total Eclipsa the Moon", after Star talks about the events of "Monster Bash" where Miss Heinous was revealed to be Eclipsa's daughter, Moon visits Eclipsa to ask her if Festivia Butterfly was really her daughter. Eclipsa denies this and suggests going to the archive to find out the truth, offering her help. Moon declines at first, but changes her mind when she realizes how much Eclipsa misses her daughter. They go to the archive but find that Meteora's record was erased, saddening Eclipsa, but Moon reassures her, telling her that Meteora is alive.
In "Butterfly Trap", Moon, Eclipsa, and Star use the trial to find out what happened to Meteora, showing how much Moon starts to trust Eclipsa.
In "Tough Love", Moon and Eclipsa try to find Meteora. After Moon gets blasted by Meteora after Eclipsa interfered Moon's attack, she seemed distressed when Moon opened a portal and went to the Magic Realm.
Moonclipsa got a little popular after "Total Eclipsa the Moon" aired, when Eclipsa helped Moon get to the archive. People contradicted that Moon and Eclipsa are possible relatives, which made shippers change their minds about the ship. When "Butterfly Trap" revealed that Moon and Eclipsa aren't related, people got comfortable with shipping it, but it isn't very popular.
Moon and Eclipsa are shown to care about each other, but each have another love interest, River being with Moon and Globgor being with Eclipsa, so this ship is unlikely to turn into a romantic relationship.