Shaymin did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Wait until nighttime, Freeze Shaymin, Put Shaymin in a PC Box
Shaymin (Japanese: シェイミ Shaymin) is a Grass-type Legendary Pokémon.
While it is not known to evolve into or from another Pokemon, it has a second form activated by using a Gracidea flower in the daytime. Its original form, Land form, will then become sky form.
Shaymin was officially revealed in February 2008, when it was listed as a star of Giratina and the Sky Warrior. In early June of the same year, its sky form was revealed, which takes on the Flying type as a secondary type.
Shaymin is a small, white hedgehog-like Pokemon. In land form, it has green grass-like fur on its back and a pink flower with two leaves on each side of its head, which resembles the Gracidea flower. Several Gracidea-like flowers also appear on its back whenever it feels comfortable, but when it senses an impending danger, it rapidly hides it back. Its legs are short and its underside is plump. Shaymin is the smallest Legendary Pokemon to date. In sky form, it has a slender, canine appearance with resemblance of a small reindeer. The fur on its back becomes a Mohawk, and it has a red flower petal on the right side of its neck, resembling a scarf or cape. It has flat, white ears resembling wings, a small ruff on the front of its neck, and a stumpy tail. Shaymin will change into sky form and back if it touches a Gracidea. It reverts to land form at night or if it is frozen. Shaymin can instantly purify any polluted area of all impurities in the air and transform it into a lush field of flowers. It takes in the polluted air, purifies it inside its body, breaks it down into water and light, and releases the purified substance in a violent, explosive burst. Its power varies on the type of pollution absorbed. Shaymin can also communicate with telepathy and sense the gratitude of others.
Each season, Shaymin gathers with others in a flower field somewhere and migrates from there. This behavior is called Flower Carrying because a new field of flowers grow where it lands. Shaymin is also attracted to areas where there is a lot of gratitude. Its personality is almost opposite with each form: in land form, it is shy and easily scared, while in sky form, it is courageous and playful. If wet, it shakes itself to dry itself off, and exhibits the behavior of scratching itself with a hind leg. Shaymin lives in fields of flowers. Since it camouflages by curling itself up, it can easily escape people's notice. It has been seen liking sweet food. Shaymin is the only known Pokemon to know seed flare. In his ultimate form, he is depicted as a Pegasus stallion with white fur coat, green eyes, green hooves, red ascot, green mane and tail. His cutie mark is a red kite shield with a white plant stem.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Like Darkrai, despite being an event-exclusive Legendary Pokémon, both the Surf glitch and tweaking are able to allow the player to access the Flower Paradise without the event having been activated.
This has been rectified in Pokémon Platinum, as neither Pokémon will appear without the event, even if the player manages to access their area.
Land Forme Shaymin is the first and the only (not counting Arceus with the Meadow Plate) pure Grass-type Legendary Pokémon.
Although Shaymin is a Legendary Pokémon, normal wild Pokémon battle music plays while battling it. It shares this trait with Cresselia, Latias, and Latios.
Out of the these, Shaymin is the only one that doesn't roam around.
Shaymin is implied to be behind the creation of Floaroma Town, as one person notes it was a barren wasteland until one day flowers mysteriously covered it all after someone gave thanks for life's blessings. Additionally, the woman who gives the player a Gracidea flower can be found in Floaroma Town.
Marley makes brief references to Shaymin in Pokémon Diamond, Pearl, and Platinum if spoken with during the player's travel with her in Victory Road. She wants to reach the smooth rock on Route 224. Additionally, if a Shaymin is in the player's party, she will take notice.
Shaymin seems to appear only when someone gives thanks for a significant blessing in their life. A girl in Floaroma Town states that the flowers the town is famous for appeared after someone gave thanks for nature's blessings. With Oak's Letter, Shaymin will lead the player to Flower Paradise after they give thanks for their Pokémon journey at the white rock on Route 224.
Shaymin's Sky Forme has a different cry than its Land Forme.
Despite this, the only cry used in Pokémon Ranger: Guardian Signs is the one of its Land Forme.
Due to the Pokédex only registering the first Forme's cry, it is impossible to listen to the Sky Forme's cry on it. This is because Shaymin traded in their Sky Forme revert to Land Forme, and wild Shaymin are always in their Land Forme. Also, Pokémon battled between players are not registered in the Pokédex, meaning that it is impossible to register a Sky Forme Shaymin before the Land Forme. It shares this trait with the starter Pikachu in Pokémon Yellow. In Generation V, the Pokédex allows switching between which form is the primary one displayed, therefore allowing Sky Forme's cry to be listened to.
Shaymin is tied with Celebi for highest base stat total of all Grass-type Pokémon.
A Shaymin caught at the Flower Paradise in Pokémon Platinum will be a fateful encounter Pokémon, making it the only Pokémon able to be caught from the wild that has this status. This is to allow it to transform into Sky Forme, as non-fateful Shaymin cannot transform.
This may be part of the reason why Oak's Letter was never released for distribution to Diamond and Pearl, as the Shaymin in those games, even if it is caught legitimately, will not be a fateful encounter Shaymin and thus not be able to transform. The reason behind disallowing this was probably to disallow those who had cheated to get Shaymin and those who used the Surf glitch and tweaking to do so from obtaining the otherwise-special Sky Forme Shaymin.
Sky Forme Shaymin has the highest base Speed of all Grass types.
Land Forme Shaymin is the shortest Legendary Pokémon.
Shaymin is based on a hedgehog. However, its white body and the grass-like fur on its back makes it somewhat resemble a chia pet as well. Moreover, when Shaymin (Land Forme) blooms with flowers, as seen in the anime, Shaymin appears as a bouquet of flowers, which serves to emphasize Shaymin's role as the Gratitude Pokémon. On the other hand, Shaymin's Sky Forme shares most of its traits with a small, young terrier-type dog, but its sprightly behavior, its affinity for flowers, and its ability to fly bring to mind fairies. Shaymin's Sky Forme has a few aspects that resemble that of a reindeer as well.
Shaymin may be a combination of 謝 xiè (Chinese for thanks/gratitude) or ジェイド jeido (jade, one of Shaymin's most dominant colors) and 蝟 harinezumi (hedgehog). It may also involve shaman (a mystic) or stamen (a plant part). Alternatively, it may be a corruption of םשמי Shamayim (Hebrew for heaven/sky), correlating directly with Shaymin's Sky Forme.
Shaymin's Pokémon Mystery Dungeon: Explorers of Sky portrait
Shaymin's sprite, as seen in Pokémon Black & White
Shaymin's official artwork from Pokémon Mystery Dungeon: Explorers of Sky
Shaymin's Dream World artwork
Shaymin's artwork from Pokémon Platinum's Flower Paradise event