The puzzle is to separate the star from the snake. Once done you'll then have the challenge (some say even harder) to put the star back in the snake loop.
It looks like it should not be too hard to do so definitely a puzzle to pass around.
This puzzle was one of the first cast metal puzzles ever made. It was seen in Stanyon's 1905 Novelties Catalog under the name "Star and Garter Puzzle". Historical information courtesy J.Slocum & J.Botermans published in "Puzzles Old and New" (c)1986.Size: The longest dimension of the loop is75mm. Point to point the star is 50mm. Presented on a red card inside a window faced brown card box (75mm x 115mm x 45mm) with solution enclosed.