The 1982 film ET prominently featured Reese's Pieces Candy (ET's favorite treat). I guess Reese's couldn't get ET for their ads, so they came up with this alien character as a substitute. In the commercials, this character was portrayed with a puppet and an actor in a costume, just like ET was.
I thought ET was much cuter and more appealing than this creature.
As a kid, I had a stuffed ET that I loved and I was so excited to get it for Christmas. He was stored in the attic years later, and when I found him again, his leather-like skin had cracked off the plush body and peeled away. So if you have an ET doll in your attic, he may have shed his skin!