Just adorable! A complete set of six Walter Bosse style vintage stacking metal hedgehogs.
Designed by Walter Bosse in the 1950s these are the Greek copies/interpretations, probably 1960s vintage. (The design was not copyrighted). The largest two hedgehogs have the Greek logos internally, along with 'Made in Greece and a deer-like logo with 'N ... A, 1947'. The Greek and Russian versions were cruder with more visible seams - see close up details. 
Probably solid copper but designed to look like bronze, they have a greeny grey verdigris patina with copper highlights. There are details in the casting on the spines, eyes, ears etc, see photos. This cast metal set was produced either as a promotional giveaway or as souvenirs. Intended as a set of six ashtrays, but more ornamental and for display. Stacked - 11 x 7 x 6.5cm. 
They're in good vintage condition with some ageing. Some internal marks from use and natural oxidation, mostly between the spines, making some areas aged green/grey (specially the smallest hog). They may polish up more.
Price includes P&P to the UK.