Jürgen Hubert quoted Schlesische Sagen 1 - Spuk- und Gespenstersagen by Richard Kühnau (Schlesische Sagen, #1)
If someone walks through the Jüschke (a forested gorge between Hollenau and Birgwitz) at midnight, an fiery foal jumps on their back. It makes the person carry it for a while, and then suddenly vanishes. Based on the location where it appears, it is called the "Jüschkefüllen" ("Jüschke Foal").
— Schlesische Sagen 1 - Spuk- und Gespenstersagen by Richard Kühnau (Schlesische Sagen, #1) (Page 520)
I want to stress that strange things jumping on the backs of lone wanderers at night is an extremely common occurrence in German #folklore .
Really, it's probably best to stay home at night.