If you’re a sushi lover, you’ve invariably had—or at least seen—kappa maki. It’s a sushi roll (maki) filled with cucumber, and often garnished with sesame seeds.

Most of us assumed that kappa is the Japanese word for cucumber. Today we discovered differently.

The kappa is a well-known Japanese mythological creature, a water imp that inhabits rivers and ponds.

Threats of the kappa have been used to warn children of the dangers lurking in rivers and lakes. A kappa may try to lure them into water, and pull them down.

Tke kappa is a trickster. It is typically depicted as roughly humanoid with scaly reptilian skin, about the size of a child.

Cucumber is their favorite meal. Hence, kappa maki was named for them. The Japanese word for regular cucumber is kyuuri.

Here’s more about the kappa.