Source: https://www.pixiv.net/en/artworks/78274357
From the artist:
"Bon (Obon) is one of the Buddhist events to perform religious service to the spirits of one's ancestors and deceased in Japan.
In some areas cucumbers and eggplants may be served as vehicles that transport spirits.
Cucumbers can be thought of as vehicles that pick them up as fast-paced horses. On the other hand, the eggplant is a slow-legged cow that sends spirits slowly.
These are called Syoryouma(精霊馬)."