These are SegaPrize plushes, which came out in a whole set of characters for Sonic Adventure 2 Battle. They all had the same half/half tag, seen here.

These plushes were always highly prized for their quality materials, large size & excellent structure.

With these detailed photos, you can see that it's all true. Look at Rouge's face & expression! Each nose is correct, & the mouths are embroidered on. They even got her pink lip. The wings are big & each bit of hair at the base of her head is sculpted nicely. Tails is just as good, his expression is really cute, & the proportions are all good too. It's no wonder these dolls are so expensive and sought-after.