We're off to save the world from a scary alien fetus!
Giygas had a plan for world domination, and he would have gotten away with it, if it wasn't for the meddling kids pictured above. Yes, due to the combined efforts of Ness, Paula, Jeff, and Poo, the alien known as Giygas who planned to conquer Earth was bested by time traveling youngins who destroyed him at the birth of his power in the distant past. But how did it get to that point? How did a boy woken up in the middle of the night by a meteorite end up on a quest to save the world with three other people who he never met before but ended up forging a bond with, a bond stronger than steel? By looking at each character from Earthbound and the role they play in its intricate story, we can see how one as foul as Giygas managed to be bested by children who weren't even at the "angsty teenager" phase of life.
That bat has SMAASSSHHHd its way to victory many a time throughout Ness' journey
Main protagonist Ness starts out Earthbound asleep in his bed until a loud noise startles him awake. Intrigued and unafraid, he sets out to investigate, and would have gone in his jammies because that's how few fucks he gives. Luckily, his momma makes him wear his iconic outfit you see above, and Ness' little nighttime excursion leads him to a flying insect named Buzz Buzz who warns him of Giygas and how Ness must one day defeat him with the power of three friends who are, as of yet, unknown to him. Pretty heavy stuff for a kid! Nevertheless, Ness is a certified badass who spends a good chunk of Earthbound on his own (at least in the beginning). He hits hard with bats, yo-yos, and slingshots, knows some Rockin' PSI magic moves that do tons of damage to baddies (especially New Age Retro Hippies), and has heart and courage in spades; and yet, Ness is human, too.
Ness makes mistakes (him and his friends are ambushed in the middle of the game and are even drugged at one point), explores the innermost recesses of his mind to unlock his full power even though he is completely naked (hey, it's his own vision, I'm not judging), and misses home from time to time (he needs to call his house and hear his mother's voice in order to cure him of homesickness). Hell, his dad is never home and just wires him money and saves his game, which would scar most kids his age, but Ness doesn't have time for that; he has to save the world from certain destruction. Ness is a heavily burdened character, but fortunately, he doesn't have to do everything alone.
She may look sweet, but she'll knock your ass out with a frying pan
Ness' journey eventually leads him to a kidnapped girl named Paula, who reaches out to him in his dreams, asking him to rescue her from crazy cultists who want to turn the world blue. Once Ness is with Paula, he can no longer ride a bicycle, but as a player, you are just relieved as all hell to have someone to help you fight goddamn burning Territorial Oaks who sap your HP like a kid drinking a chocolate milkshake. Paula is weak at first because at the time you meet her, you are levels ahead of her. Given enough experience, Paula.....never really gets stronger physically and is frailer than Ness and the others, but her PSI magic is on POINT. She can freeze, burn, and shock enemies, sap their PP, shield her friends, and temporarily raise their offense and defense. She also swings a frying pan like nobody's business. Paula is also the only character who prays, which bathes you in a heavenly light, that sometimes heals your party somewhat or just starts making you cry so you miss all of your attacks. Pretty useless, right? Right, until the very end of the game, because Giygas can only be defeated through the power of prayer.
Indeed, Paula must be kept alive to reach out to everyone you encountered throughout the game, including you, the player (why else would the game ask you for your name specifically, fun and games? This isn't amateur hour). Paula is a powerful ally, and is the only person in Ness' group of friends who can contact others telepathically. Speaking of that...
Bottle rockets, yo
After Ness runs into an ambush and gets captured along with Paula, there appears to be no escape for our heroes. Luckily, Paula reaches out to a young boy named Jeff, son of a genius scientist and member of an all boy school. Jeff is miles away from Ness and Paula, but senses the urgency in Paula's message. Like Ness, he just leaves school at a moment's notice because YOLO. He befriends a monkey, a Lock Ness monster, and gets laser guns and bottle rockets to blow shit up. Jeff manages to save the gang by crashing his ship into an underground prison beneath graves because the game is pretty fucked up at that point (it gets way weirder, so it's not like this part is the apex of Earthbound).
Now, onto abilities: Jeff can spy on enemies and learn their stats and weaknesses, though he cannot use PSI. His bottle rockets do crazy amounts of damage, and any broken shit Ness and his friends pick up can be fixed by Jeff after a good night's sleep (provided his IQ is high enough). Jeff may not be able to shoot lightning out of his ass like the rest of his friends, but they love him anyway, and value his abilities and smarts. The trio of pals last together for quite some time, until they partake in eating some cake that causes them all to trip balls...
Poo, seen here with a sword 95% of you didn't even know he could wield
So who steps up to save our heroes from delicious psychedelic sweets? The unfortunately named Poo, that's who! Poo is a monk from a faraway land who heeds the call to save the gang after some really scary meditation. It's terrifying, actually: Poo loses his arms, legs, eyes, and ears during the ordeal, and the SNES uses clever audio and visual cues to drive this point home. It is only when Poo gives up his earthly body during training that he is truly free, and he teleports to save Ness and company (provided he has a running start). Poo is a beast: he knows a lot of the offensive PSI Paula wields, has a unique one of his own called PSI Starstorm that obliterates anything in its path, and can go the entirety of Earthbound beating foes with his bare fists (his Sword of Kings has a 1 in 128 chance of being dropped by one enemy in the game at one specific area, so good luck getting that shit).
Also, since Poo is constantly trying to better himself even after losing his limbs figuratively during a trance, he will up and leave your party to get some training done without warning. Poo is a loose cannon that plays by his own rules like the rest of the Earthbound kids, but he sticks with everyone after achieving his ultimate form of PSI Starstorm, even when their brains are put into robots so our heroes can travel back in time to stop Giygas in his infancy.
Thanks to scientists young and old, Mr. Saturn, you, the player, the entire cast of Earthbound, and of course, our meddling kids, Giygas is defeated and peace returns to Earth. Back in the present, the four friends part ways, with Ness taking Paula home and returning to his loving mother, sister, and dog. Throughout Earthbound, our young saviors have seen some serious shit: zombies, cultists, aliens, ghosts, robots, and Abstract Art, to name a few. They have gotten sick, stayed at hotels, eaten burgers, seen some musical shows, explored an entire dungeon that was also a man, and even bought a dilapidated house together. You can't not form an everlasting bond after all that. Through the power of individual strengths combining together into a fusion of love, courage, and trust, it's no wonder that even someone as horrifying as Giygas...
WTF IS HAPPENING?!
...never had a chance against these four.