I'm not sure why you bothered to use the Japanese names here when you've
already started spelling Mewtwo in English.

Didn't anyone notice? A lot of Pokemon never had their names changed.
Mewtwo's original name is Myuutsuu, which is a romanji version of that name.
Here's the list of Pokemon with the same name.

Pikachu
Zubat
Kabuto
Porygon
Dodrio
Gengar
Caterpie
Seadra
Raichu
Nidoqueen
Doduo
Parasect
Shellder
Golduck
Omanyte
Golbat
Arbok
Lapras
Kabutops
Nidorina
Paras
Kingler
Starmie
Nidorino
Persian
Mewtwo
Butterfree
Dugtrio
Nidoking
Omastar
Ponyta
Togepi

Yup. 32 of 'em keep their original names.

Togepi: PRRRRRIIIIIIIIII!!!!!!!!!!!!!!!!!!!!

[Mewtwo becomes extremely annoyed.]

  >C'mon, kill Topegi!!!

Sorry, but unlike gene-splicing scientists, Pokemon are much tougher, and
everyone will survive to be blown up by Mewtwo's temper again and again and
again. Mwahahahahahahaaaaa!!!!!!!!!! El Pollo Diablo, the hidden
Flying/Demon Pokemon, will rule us all!!!!!!!!!!!!!!!!!!!!!

[Mewtwo's eyes start to glow blue, and the grond starts to crack and
explode. Mewtwo's rage grows, and the others scream and try to >escape.

They

fail. Togepi and the others are quickly consumed in the flames of

Mewtwo's

anger.  He blows up more of the theme park, and the fire starts to

consume

everything. He hovers above the ground and parts the fire around

him,

making
himself look extremely cool. A sphere forms around him and starts

growing.

The park is now shown in the distance. A bright plue pillar of energy

comes

up from it, then an explosion takes place. Smoke rises from the >remains

of

the theme park. Mewtwo flies away to find a better fanfic author to >work
for.]

  >Shoot, and here I was, hoping for Super-Saiya-Mewtwo

Nope, but Mewtwo does do that pillar thing when he's pissed. I guess it's
the Pokemon equivalent of Super-Sayajin.

That wasn't so bad. The humor comes from the complete differences in
character and the reactions. Pikachu is cute, innocent, and carefree, and
Mewtwo is violent, depressed, and philosophical.

 > An interesting little spamfic, although I wish Pikachu got thrashed by

Mewtwo... heh, heh.

Oh, he will be. He will be. Heheheheheh.