We’ve covered quite a few unusual robots from Japan in the past, but the SiliFulin, a robot tail designed specifically for humans, is definitely among the weirdest models. You can wear the robot around your waist, where it reacts to your movements.

Every human embryo has a (quite large) tail, which is gradually absorbed by the growing body. But the SiliFulin intends to give users back the experience of walking around with a tail, a part of the body human beings lost during evolution.

Designed by Japanese media artist Ryota Kuwakubo, the robot features a number of servo motors that power multiple joints, making them move based on the way you walk.

Here’s a video showing the SiliFulin in action (I’ll leave all form factor-related jokes to you):