Until recently, it was generally believed that the design for Pikachu was based on the mouse.
However, recent Japanese research suggests that Pikachu may have actually been modeled off thecacera pacifica, a species of sea slug found in the Indian and Western Pacific Oceans.
The findings have stirred the Japanese public who have long held Pikachu in high regard as a cultural icon and international delegate of adorable.
Even to the untrained eye, the similarities between Pikachu and thecacera pacifica are striking: yellow body, black-tipped pointy ears, forced evolution via thunderstone.
In Japan, thecacera pacifica even carries the nickname ‘Pikachu sea slug’ and is the slug of choice among many Japanese Pokémon fans (tough luck, Slugma ).
For those interested in catching a thecacera pacifica, they can be found at the Izu Peninsula, Bonin Islands, Yakushima or one of the several other costal island regions in Japan.
All islands can be accessed by ferry or HM03. Contact the Safari Zone for more details.
Source: YouTube（lld524） 、 umiushi-zukan.com （石垣潜水堂）
[ Read in Japanese ]