Shiinotic is a large, white Pokémon that resembles a mushroom. Its slim body is similar to a stalk, and it has a large, purple mushroom cap on its head. Its eyes are large and black with pale green half-circle markings on the outer side. Unlike its pre-evolution, it possesses a visible mouth, which is medium-sized and black. The ends of its long, thin arms split into three pale green tips that act as fingers. Its small feet and rounded lower half are light pink in color, and it has several small, light pink bumps around its midsection. The mushroom cap on its head possesses pale green oval markings and a pale green underside, which are capable of illuminating.
Living in forests, Shiinotic fights over territory with Parasect, often coating the area in spores. The strange lights that it emits can confuse people who enter its habitat at night, causing them to be unable to ever find their way home again. The flickering spores that it releases cause drowsiness. It takes advantage when its prey is asleep, feeding on them by sucking in their energy through the tips of its arms. It can then choose to transmit this energy to a weakened member of its kind.
Shiinotic can be seen as a counterpart to Parasect. Both share the Grass type and the same base stat totals, both can learn Spore, and both appeared as trial Pokémon of the Lush Jungle in Pokémon Sun and Moon depending on the game version, with Shiinotic being found in Pokémon Moon and Parasect in Pokémon Sun.
Shiinotic may be based on bioluminescent mushrooms such as those of the genus Mycena. It also features a volval sac and wide brimmed warty cap, which are trademarks of the Amanita family. Its Fairy type may be due to the fact that both families are known to grow in fairy rings, or it may possibly be a reference to fairy fire. From its name, Shiinotic may have some aspects of the shiitake mushroom as well. Due to its habits of confusing people in the woods with its lights, it may also be based off the supernatural interpretation of will-o'-the-wisps.
Due to its emphasis on shining light, and some of its foreign names including it, Shiinotic may also intentionally resemble a lamp.
Shiinotic may be a combination of shiitake, shine, and hypnotic.
Mashade may be a combination of mushroom and shade.