Shuckle seems to be based on an
endolith, an organism that lives inside porous rocks or animal shells. Given its category, the Mold Pokémon, Shuckle may be based on a fungus or mold variety of endolith. Its category could also allude to fungi such as
cedar-apple rust, which bears a strong resemblance to Shuckle, or fungi-like
slime molds.
Given its
Bug typing, Shuckle may also draw inspiration from
scale insects—small, shelled parasites that produce a sweet fluid called
honeydew that attracts other insects. In particular, it may be based on the
barnacle scale, with characteristics of actual
barnacles. This species is part of the
Coccidae family, also known as "tortoise scales", which may explain Shuckle's resemblance to a
turtle or a
tortoise. It could also be seen as a reference to the
food fermentation process, with its
Rock type alluding to the pottery used to store and ferment aliments in some cultures, and its Pokémon category referring to some fungi used in
cultured foods.
Shuckle may also have been based on certain varieties of
mollusk, as it shares some characteristics with them, including the shell, the muscular but limp-seeming feet, the use of acids to receive food or to break down obstacles, the liking for fermented foods, and living close to the water. Its worm-like aspect may also take inspiration from a
nematode.
Shuckle may be a combination of shuck (husk) or shackle and barnacle or turtle.
Tsubotsubo may be derived from 壺 tsubo (jar) and 富士壺 fujitsubo (acorn barnacle).