Here's a classic Sonic plush, uncommon by nature!
This plush is 52 inches high (a giant, especially in its time!) and was made by Caltoy. It is VERY heavy at 18-20 lbs.

It is rare because you couldn't buy it, you could only WIN it from a Best Buy store. Best Buy sells electronics, appliances computer stuff...and of course video games. Some time in 1993, each store had a contest of some kind (possibly like a free raffle or a prize draw) to stir up business. The winner got this giant Sonic plush....

so there are probably only as many of them as there were Bestbuy stores at that time! The plush itself is just ok, with a whopper nose and somewhat crude hands for the size. It is also a tad fat, and the case of 'big body' is really exposed in the shot from behind-- but over all pretty ok looking especially for something that big done that early on. Certainly, it's a super interesting and rare plush to have!