Mooncake first appears in Chapter One of the series. Gary initially mistakes Mooncake for a pixel until Mooncake flies into his helmet, startling him.
Mooncake is a new species of alien originally discovered by the Scarlet Lance fleet near a star about to go supernova. His discovery prompted the destruction of the Scarlet Lance by the Lord Commander after the ship refused to give him up. The Lord Commander subsequently began hunting him before the Final Space series begins.
When Gary finds him at the start of the series, he names Mooncake after a childhood pet; a caterpillar given to him by his father, John Goodspeed, before he passed on in front of his son and the caterpillar. During chapter 8, it is shown that when the energy wave and the antimatter blast closed Final Space, Mooncake was created. This is again confirmed in "Arachnitects".
Appearance
Mooncake's design is incredibly simple. He has green skin and no visible nose. His head is oval shaped, with two stubby appendages and antenna with spherical tips.
Personality
Mooncake is friendly especially to Gary. He is a powerful "planet destroyer" who hates himself for what he was made to do. Mooncake is very open to Gary since he seems to be the very first life form he has met that is okay with who Mooncake is. Mooncake is a "face hugger" according to Gary, but he dislikes the Lord Commander and his intentions on keeping himself alive by exploiting Mooncake as the key to opening Final Space.
Mooncake is very loyal, cheerful and friendly to everyone else, but specially Gary and will often put his life on the line to protect him. He has also picked up on a few of Gary's character traits along the way, such as when he appears annoyed by KVN.
More in season two, Mooncake has shown degrees of intelligence, enough to play a chess-like game with Clarence at the end of "Arachnitects".
Powers and Abilities
Mooncake can fire large green energy blasts from his body capable of destroying nearly everything that they touch, including planets (but not including the Lord Commander). He can change the power of these blasts at will.
He can also levitate his body unaided and fly incredibly fast through space, even with Gary and Avocato in tow. He is also very intelligent and appears to be able to understand English and emotions. Mooncake can also breathe in space without air.
It is revealed in "The Toro Regata" that Mooncake's energy powers have been completely drained by the Lord Commander's death ray. In "Arachnitects", his powers are restored when he rescues Gary and seals the breach in Final Space, preventing Invictus from escaping.
In Descent Into Darkness he show the capacity of create a vacun to eat thing, using this ability to save KVN. He maybe learn that for the incident with the pancakes
Relationships
Gary - Best Friend
Mooncake found Gary by "flying" into him from an unknown location, possibly from the Lord Commander chasing him. Both share a connection and have a common goal, with Gary choosing to see the good in Mooncake rather than his destructive potential. Mooncake is very friendly towards Gary, and Gary is very loyal to Mooncake. Gary would do anything to protect Mooncake, and Mooncake often puts himself at risk to save Gary.
In "Notorious Mrs. Goodspeed" Mooncake is shown to quickly get jealous of Sheryl Goodspeed, as Gary is now spending time with his estranged mother. As a result, he takes to eating almost anything he can find, though this is quickly resolved by the end of the episode.
Avocato - Friend
Avocato has been looking for Mooncake all over the galaxy to hand over to Lord Commander. However, after playing cards with Gary, he warms up to Mooncake and even trusts him, as shown when Avocato was shrunk from his normal size in chapter 5. Mooncake trusts Avocato, and even allowed him to ride on his back.
kvn - Friend
Mooncake appears to be more lenient and friendly towards KVN out of most people within the Galaxy One crew, though he does occasionally appear annoyed by KVN. He and KVN tend to be paired in some of the most dire of situations in the show, whether it'd be forced or a choice.
Lord Commander - Enemy
The Lord Commander views Mooncake as nothing more than a means to an end and seeks to use his immense power to reach Final Space. Mooncake shows intense dislike towards him, and also fear.
Nightfall - Former Ally
During chapter 7, when Nightfall had short meetings with Mooncake earlier in the season, she tries to kill him in hopes of saving the timeline, but is ultimately stopped by Gary. Mooncake seems to bear no ill will towards her for this, and even flies over to her in "The Toro Regata" after meeting with her again. During season two it can be assumed that they grew close, close enough for him to cry before sacrificing her according to her wishes so Bolo would be freed in "The Sixth Key".
