Chara vs Rick

Chara 

Chara is one the first human to venture out to the underground. 

Abilities: Possession, Incorporeal, Immortality (Type 8), Timeline creation and destruction, Soul Manipulation, Determination, Time Manipulation, Reality Manipulation, Acausality, Ability to SAVE and LOAD, Regeneration (Mid-Godly)

Attack Potency: Likely Multiverse level (Destroyed reality/the game itself, which contained countless timelines. While the exact number is unknown, the sheer number of resets performed by characters such as Flowey, along with the fact that a number composed of 216 'nines' is measurable at the end of the genocide route, would easily put the number in the 2-B range.)

Speed: At least Massively Hypersonic+, likely much higher while possessing Frisk (Capable of aimdodging lasers fired from Sans' Gasterblasters, as well  as Vulkin's lightning. Superior to Napstablook.), Omnipresent after reaching their "absolute" (Exists as an abstract entity whose influence is everywhere in all possible timelines, as well as continuing to exist everywhere in the empty void after reality has been destroyed)

Durability: Likely Multiverse level (Completely unaffected by their own destruction of the game, Exists as an abstract concept that will be brought back as long as someone with enough Determination exists), likely much higher (Ability to SAVE and LOAD makes them extremely difficult to destroy even in physical form. In their true form, Chara exists as an abstract concept capable of manifesting no      matter what as long as someone experiences the drive, will, and feelings they embody, thus making them nearly impossible to actually destroy or get rid of. Returned to existence after years of non-existence simply from Frisk's entrance into the Underground.)

Rick Sanchez

He is a genius scientist whose alcoholism and reckless, sociopathic behavior are a source of concern for his daughter's family over the safety of their son, Morty.

Abilities: Superhuman Intelligence, Peak Human Strength | Create portals to others universes, freeze time, move buildings to other universes, Alter matter, Create artificial intelligence, FTL travel, Cloning, Vaporize people, Size alteration

Intelligence: Supergenius. He was able to create a miniature sentient robot just to pass butter and grant a dog highly advanced intelligence in only a few seconds. He was also able to tell when he was inside a simulation inside a simulation inside another simulation     and still flawlessly trick the Zigerion scammers into blowing themselves up.

   His Inventions:

- Portal Gun: A gun that rips a hole in space-time, allowing travel to any point in any universe. Rick can also use this as a makeshift weapon, as opening a portal inside another being rips them in two.

- Meeseeks Button: Summons a bunch of immortal creatures that will perform one task before dying. Become more insane the longer they exist due to hours seeming like an eternity, to them. Meeseeks are apparently completely unable to die until their task is completed, and giving them a task which is seemingly impossible to complete will eventually result in the summoned Meeseeks resorting to the most drastic measures to complete the task by technicality.

- Size Shifting: Able to affect people and objects, either making them tiny enough to fit inside someone or making them grow to the size of a continent.

- Love Potions/Diseases: Created a virus that made whoever it was used on fall in love with Morty (Except those genetically related to him), but due to it being flu season, the substance piggybacked on the flu and began to spread; he created two others to counter that. The first turned everyone on the planet into praying mantis monsters, while the second turned everyone into Cronenberg monsters.

- Time Freeze: Freezes time on a universal scale. Due to technology stolen from the 4th dimension, Rick can do this with the press of a button.

- Concentrated Dark Matter: A method used for travelling faster than anyone else in the universe; similar chemical reactions cause massive explosions. A handful of the components mixed incorrectly resulted in an explosion the size of Jupiter.

- Anti-Matter Gun: A pistol that shoots anti-matter. Capable of even killing trans-dimensional higher beings immune to traditional matter and energy based attacks.

- Particle Watch: A wristwatch that fires a concentrated particle beam. Completely destroys the target on a subatomic level.

- Freeze Ray: Completely freezes organic targets, turning them into incredibly fragile icy statues. Since the affects can be undone, this is used in the rare case of nonviolent neutralization. Comes in taser and gun form.

- Curse Remover: A device which can remove magical properties from a wide variety of different things. Since it is able to remove certain effects while leaving others intact, Rick used this device to turn cursed objects into completely beneficial ones (i.e. turning a pair of boxing gloves which would cause the wearer to be stuck reliving a single fight for all eternity into a pair of time traveling mittens).

- Dream Inceptors: A small device which, when implanted into the ear of an unconscious sentient being, allows the user to travel into the being's dreams, potentially implanting new thoughts and influencing the behavior of the target once they wake up.

 Ready to die?

 OOH.. IS ON YOU LITTLE BITCH!

Here are the fanart I've just found which I recommend for you to go check it out. 

Chara (Undertale) - Stop looking at me like that!

Middle-Fingered Rick (sorry couldn't find the orginal artist  )