It is a tall building made entirely of different colored ice cream scoops and various candies. It has a glass door with candy frames around it and an ice cream shaped sign reading "Ice Cream" in capital letters with an arrow pointing to the entrance. It is very colorful and bright, and appears to have a rainbow formed in the back of it.
Role in episode
It is the place where Patrick goes to obtain free ice cream from his coupon. Upon entering the store, he sees lots of ice cream, including a giant cart filled with it. Eventually, he gets kicked out and goes to the Ice Cream King.
The inside of this Ice Cream store seems to reference the film Willy Wonka & the Chocolate Factory. The design is extremely similar, having the chocolate "river" from the movie, as well as an eccentric owner.