This series revolves around a little alien girl named Stella and her alien dog, Firgu, as they spend their lives on their home planet while getting into weird situations.
- Stella (voiced by Tara Strong) - a smart, little alien girl who loves adventures and is very kind.
- Firgu (vocal effects by Dee Bradley Baker) - Stella's pet alien dog who follows her around.
- Orion (voiced by Grey Griffin) - a 1-year old alien who is Stella's baby brother.
- Halley (voiced by Vanessa Marshall) - a 17-year old alien who is Stella's older sister and usually has an unhealthy relationship with Stella, often picking on her and calling her a dork.
- Leo and Ariel (voiced by Corey Burton and Carolyn Lawrence, respectively) - Stella, Orion, and Halley's parents.
- Dr. Armadeus Smellyfoot (voiced by Nolan North) - a geeky scientist who has a temper problem. He despises being called by his last name.
- Leggard (voiced by Eric Bauza) - an alien who is Dr. Armadeus' lab partner.
- Delilah (voiced by Kari Wahlgren) - a little alien girl who is Stella's best friend.
- Felix (voiced by Jason Spisak) - an alien boy who is an emo.
- Brian (voiced by Asher Bishop) - an alien boy who loves playing games and doing dares.
- Dixie (voiced by Dayci Brookshire) - a little alien girl with a somewhat snarky attitude who can sometimes get rather bossy and likes fashion.
- The Bean Guy (voiced by Rosearik Riki Simons) - a strange imp alien who delivers beans that cause people to appear in strange worlds.
- The Mecha Horse (vocal effects by Frank Welker) - a robot horse that Stella and Firgu encountered.
- Lance Aston (voiced by Jerry Trainor) - a human astronaut who ended up having his rocket crash onto Stella's home planet.
- Gary (voiced by Jennifer Hale) - a shy alien boy who Stella made friends with.
- Hedgy (vocal effects by Frank Welker) - a hedgehog-like creature who Stella and Delilah encountered around their school and was decided to be kept as a pet by Delilah.
- Kitroo (vocal effects by Tara Strong) - an alien cat who was saved by Stella and Firgu during a flood. He now lives with Patty.
- Patty (voiced by Ashley Johnson) - a teenage alien girl who became Kitroo's owner.
- The Crazy One (voiced by John Gegenhuber) - an old alien who acts crazy and is a recurring character.
- Snab Chieftain (vocal effects by Dee Bradley Baker) - a snab who is the chieftain of the snabs.
- Frankie (also voiced by Grey Griffin) - Felix's five-year old sister who is very crazy and is known to attack others by biting them like a dog.
- Bones (vocal effects by Frank Welker) - Felix's dog who is rather easily irritated by people besides Felix's family.
- Golly Gobb (voiced by Jim Meskimen) - a goblin alien who befriended Stella and Firgu.
- The Nova Brothers, consisting of:
- Neil Nova (voiced by Tex Hammond) - an alien boy who is the leader.
- Alan Nova (voiced by Ramone Hamilton) - an alien boy who is athletic.
- Michael Nova (voiced by Jay Gragnani) - an alien boy who is chubby and loves food.
- Pete Nova (voiced by TBD) - an alien boy who is an idiot, making him the dumbest of the group.
- Buzz Nova (voiced by Sam Lavagnino) - an alien boy who is a nerd, making him the smartest of the group.
- Chief Castor (voiced by Dwight Schultz) - a strict alien who is the head of the city's police department.
- Officer Luna (voiced by TBD) - a nerdy alien officer who is one of Castor's assistants.
- Hannah (vocal effects by Grey Griffin) - a hedgehog-like creature who Hedgy has a crush on.
- The Bombird (vocal effects by Fred Tatasciore) - an ostrich-like alien creature that broke into Delilah's house.
- King Ov'ri'luz (also voiced by Corey Burton) - an old and wise alien who the Crazy One once worked with when he was younger. He was only a mentioned character prior to Older and Younger and Life of a Crazy One, where he has been seen in flashbacks.
- Prince Zel (voiced by Wil Wheaton) - an alien prince who is the son of King Ov'ri'luz.
- Jenny (voiced by Laura Bailey) - a robot who loves almost anything and was an assistant, but was given away for unknown reasons as she now roams the forest.
- Janet (voiced by Olivia Hack) - a perky alien girl from a separate planet from Stella's who is kinda weird as well.
- The Kylon (vocal effects by TBD) - a lion/gorilla-hybrid alien who befriended Stella and took him back to the zoo.
- King Cillos (voiced by Fred Tatasciore) - an evil and greedy king from another planet who wanted to take over Stella's home planet.
- The Giant Robot (voiced by Steven Blum) - a giant robot who was supposed to protect the planet, but due to an electrical problem, it started attacking people and wrecking the planet.
- Queen Coco (voiced by Ashly Burch) - an alien queen who is the ruler of the Cocoa Land.
- The Brain Monster (vocal effects also by Frank Welker) - a brain-like monster who started the whole invasion.
- The Sneaky Ninja (also voiced by Eric Bauza) - a ninja alien who was the original owner of the sneakers Stella found.
- Scoot (voiced by Carlos Alazraqui) - a tween alien who is the leader of his gang, skips school, and came up with the idea to make Stella do dangerous tasks.
- The Che-Star Duo, consisting of:
- Taylor (voiced by Melissa Fahn) - a little alien girl who everyone at her school considers one of the worst bullies in the school.
- The Gigaworm (voiced by Amy Keating Rogers) - a giant worm-like creature who caused the apocalypse in Stella's dream.
- Dr. Luna (voiced by Mindy Sterling) - a scientist who is Dr. Smellyfoot's rival.
- Sirius (voiced by Dave Wittenberg) - another scientist who is Dr. Luna's partner and is Leggard's rival.
- Vincent (voiced by Tommy Blacha) - an alien vandal who vandalized Stella's school "for the lulz".
- Jake (voiced by Mark Whitten) - a prankster alien who tried to ruin The Time of the Blessed by delivering gifts with creepy and dangerous items inside.
- The Cat Man (also voiced by Fred Tatasciore) - a cat-like humanoid creature who abducts people.
- Tara (also voiced by Tara Strong) - a clone of Stella created by Dr. Smellyfoot that ends up turning evil due to a malfunction.
- Tony (voiced by Ron Funches) - an alien criminal who broke into Stella's school to steal some files, but then fled after mistaking Stella as a demonic entity.
- Legiman (voiced by Tom Kenny) - an elf-like alien who is the leader of the group and saw Halley as their queen and kidnapped her.
- Project P.A.W. (voiced by Max Mittelman) - a project that was made to heal people, but ends up injuring them instead.
- Future Stella (also voiced by Tara Strong) - a dystopian future version of Stella who is far more sinister than her present self.
- Cutie (vocal effects by Frank Welker) - an aggressive alien bull dog who Firgu accidentally stumbled across while trying to find Stella as Cutie attempted to take him down.
- The Stream Thing (non-speaking) - a sasquatch-like alien creature that has been lurking around the national park's stream for years.
- Samuel (also voiced by Nancy Cartwright) - an alien kid from a different school who mocked Stella and her classmates while they were playing tennis.
- Noops (voiced by TBD) - another alien kid who is Samuel's best friend.
- The Alpha Wox (vocal effects by Fred Tatasciore) - a canine-like alien who made Firgu join its pack, mistaking him as one of its kind.
- The Cool Ones, consisting of:
- Pops (voiced by Kevin Michael Richardson) - a big bear-like alien who, along with his wife, own the cabin Gary went to.
- Molly (voiced by Kath Soucie) - a medium-sized bear-like creature who owns the cabin Gary went to along with her husband.
- Barney (voiced by TBD) - a small bear-like alien who is Pops and Molly's child.
- Basali (voiced by Richard Steven Horvitz) - a snake-like alien who is wanted for various reasons, as he started kidnapping dogs recently, including Firgu.
- Natalia (voiced by TBD) - a jerkish alien who has been trying to get Stella to join her in robbing a grumpy old man's house.
- Gilgan the Flag Alien (voiced by TBD) - TBD
- Ratapes (vocal effects by Frank Welker) - a rat-ape hybrid species who wander around, yet they cause mayhem whether it'd be for revenge or simply for fun.
- Mud King (vocal effects by Dee Bradley Baker) - a mud giant who is very hostile as he loves to cause chaos and leads a large group of smaller mud monsters.
- Donkey (voiced by TBD) - a completely idiotic donkey-like alien who likes to annoy kids and pets, alongside ruining their personal belongings.
- Crash McGee (voiced by TBD) - a rude teenager who became Halley's "boyfriend", yet is secretly making fun of her behind her back and was only "dating" her to do so.
- Cronen (voiced by TBD) - TBD
The series first made its way on Cartoon Network on June 3rd, 2019.
It made its international debut in Canada on Teletoon on July 12th. It premiered on Cartoon Network UK and Cartoon Network Australia and New Zealand on October 7th and October 11th, respectively. Cartoon Network Asia and Cartoon Network Pakistan premiered it on November 2nd and November 30th, respectively. Cartoon Network Italy premiered it on December 2nd, with Cartoon Network Japan premiering it on December 8th. Cartoon Network Germany, Cartoon Network CEE, Cartoon Network Africa, Cartoon Network RSEE, and Cartoon Network Nordic premiered it on December 23rd. Cartoon Network France and Cartoon Network India premiered it on January 13th, 2020 with its Boing (Spain) and Cartoon Network Portugal premiere on January 18th, 2020. Cartoon Network Korea has premiered it on February 8th, 2020. It has premiered on Cartoon Network Turkey on March 16th, 2020.
See Theme Song.
- In Cocoa Land, Firgu has been shown eating chocolate and somehow lives while in real life, chocolate is poisonous to dogs.
- It is believed that it has something to do with his alien species, that unlike dogs we see on Earth, the types of dogs Firgu is is immune to chocolate.
- This series came out the same day Howler premiered.
- This is the fifth Cartoon Network series to be created by a woman, with the first one being Animals in the Strange Land, the second one beingKodiak: The Dog Timestopper, the third being Steven Universe, and the fourth one being Summer Camp Island.
- Cartoon Network Studios: The custom animation is Stella laughing while riding Firgu.