This is a special double-faced token! On one side you get the Snake 1/1 Green Token, while on the other side there's an Old School token, the Snake Artifact 1/1 Token that gives poison counters! 
 
A Snake 1/1 Deluxe Token by Mezzocielo&Friends
 
Dimensions: 63mm x 88mm, 2.48" x 3.46" (Standard MTG Size)
Artist: Lucho
Collection: Classic
Collection Number: CC219