The Automatic Grouch is an invention created by Oscar the Grouch in Episode 0382 of Sesame Street. Though he bears little resemblance to a live Grouch, his sole purpose in life is to act as if he were a flesh and blood Grouch.
Oscar creates the machine to ensure Sesame Street won't be without a Grouch should he not be around. While he steps out for awhile, the Automatic Grouch assumes Oscar's place in his trash can and replies to all of his neighbor's queries as Oscar would, though seemingly much more harsh.
The adults conspire to get back at Oscar by reprogramming the machine. Now, it acts friendly and cordial to all who greet it. When Oscar returns, he's appalled by what's become of his creation and attempts to remedy things. As he pulls wires, the machine blows apart. Oscar doesn't mind much, claiming it as a new hunk of junk he can display in his collection.