One of the core mechanics of the Pokemon franchise is the various types the pocket monsters can be. Each Pokemon can be either one or two of the eighteen types introduced in the Pokemon games with these types affecting more than just what moves they learn or how useful they are in a battle. The entire concept of a Pokemon's design is typically centered around the primary typing of that Pokemon so if one were to alter it, the design would surely change.
This is where the limitless potential of fan art comes in. Some of these artists have taken on the task of redesigning certain Pokemon with a new type in mind. Taking the fire-type Vulpix and turning it into a poison-type or turning the aquatic Gyarados into a ground-type are merely some concepts the Pokemon fan base has produced. One fan artist, in particular, has taken one of the Hoenn starter Pokemon and designed it with a new secondary typing.
A user on Reddit named Guason_Arts redesigned Sceptile from Pokemon Ruby and Sapphire into a grass and ghost-type. Typically, Sceptile is exclusively a grass-type and is considered by some to be the best grass-type in Generation 3. Guason_Arts' rendition of the forest Pokemon turns it into a more spooky creature with a skull-like face and a chest designed after the bare ribs of a skeleton. This new Sceptile appears as if its stomach area and lower legs are made of a purple smog.
What may be the most noticeable change to Guason_Arts' Sceptile is that its lush, tree-like tail is almost completely bare of leaves. The tail now has large spikes poking out with one leaf sitting at the tip of the tail. This appears to be the only piece of fan art Guason_Arts has produced of this type, though they have created other pieces including Venusaur.
One reason this type of fan may have become such a popular trend could be the same reason the Pokemon fan base fell in love with regional variants. The concept inherently has a ton of potential as fan artists consider the various reasons a Pokemon may have adapted differently to a new climate and how those adaptations influenced its design. This idea has gained so much popularity that some fans have made their own list counting down which Pokemon most deserves a regional variant.
Fan art such as this may further amplify the excitement fans have for the upcoming Pokemon games. Many fans hope to see the concept of regional variants return and with the rumors claiming to have seen new regional variants for Pokemon Scarlet and Violet, fans will have to wait and see what Game Freak has in store for the new Pokemon games.