Now introducing... Trivianan forms!

[Lycanthropy]

Haunter's claws have become floating fists, making it a Ghost/Fighting type. It can appear out of nowhere from your shadow to punch you in the face. Be careful!

Magnemite?

 

[PageEmp]

Magnemite now has seaweed on it's body, it's head-screw is replaced by a shell, and is now Water/Electric. It also gets level up Ice beam so watch out!

Jigglypuff

 

[Adam Levine]

It is ready to Smash. It has a bandana on its head, and is a Fighting/Type.

Seaking?

 

[PageEmp]

Seaking now has rock spikes all over it's body and it's tail becomes larger. It is now Rock/Water.

Cloyster

 

[Caaethil]

Cloyster is a Water/Fairy type. Its Attack and Special Attack stats are swapped, and it loses some Defense for Special Defense, balancing them out. It is a white, more beautiful and more gentle Pokemon. Its shell is smoother.

Ditto.

 

[DyingWillFlareon]

Its still only has the move Transform, but its now pure Fairy typed and has pinker skin.
Delibird.

 

[PageEmp]

Delibird is now Water/Flying. It can now dive in a fifth of a second, and it's beak is now sharper, and it's tail has been replaced with a knife.

Tyrantrum

 

[Adam Levine]

Tyrantrum is a Water/Dragon-type, sporting a Godzilla-like appearance.

Rowlet?

 

[Meadow]

Rowlet is still a Grass/Flying-type, but it is now 10x fluffier than before! Also, it has the ability Water Absorb, which makes it even fluffier if it gets hit by a water attack! ^w^

How about a Trivianan version of Bewear?

 

[PageEmp]

Bewear is no longer Mr. Nice hugger. He has adapted to the environment to become a gangster, and is now Poison/Fighting.

Shiinotic

 

[Meadow]

Appearance-wise, Shiinotic is now a bowling pin holding an umbrella! Its typing has become Normal/Rock, and it has Sturdy as an ability.

How about Stunfisk?

 

[Cad48]

Stunfisk now lurks on the ceilings of caves and buildings to fall on you, and is thus Dark/Rock
How about Rotom

 

[PageEmp]

Rotom now becomes purple with green stripes and is now Poison/Psychic. It can now not only go in appliances but also buildings, chairs, and even boats.

Floette

 

[jombii]

Rotom now becomes purple with green stripes and is now Poison/Psychic. It can now not only go in appliances but also buildings, chairs, and even boats.

Floette

Instead of it holding a flower, it's now holding a rock. It's now a Rock-type.

ZUbat

 

[PageEmp]

Zubat grew mysterious hair out of nowhere and can now learn Hyper voice. It is also Dark/Flying now.

Sunflora

 

[Meadow]

Contrary to its name, Sunflora now resembles the moon instead of the sun! Thus, it no longer has any petals around its face. Aside from that, it is still the exact same as before!

How about Dunsparce?

 

[pkmin3033]

It is now clad in metal armour and its tail has mutated to become three times its original size. It also shoots Hyper Beams from its eyes now. Kneel before your new god.

How about...Reuniclus?

 

[PageEmp]

Reuniclus is now Psychic/Ghost. It is now gray with purple dots and looks like a real cell now.

Carracosta

 

[pkmin3033]

The shell has tripled in size and has become super spiky. Unfortunately Carracosta's limbs are now useless, but it is practically impervious to attacks and can propel itself through the water with ease with streams of bubbles from any of the openings in the shell where its limbs were previously.

Serperior

 

[Tsutarja]

Trivianan Serperior is one that has actual leaves growing out of it, and small grassy hills on top of its head to emphasize that it's the Regal Pokémon!

Fennekin?