Pennywise

It, also known as Robert “Bob” Gray and Pennywise the Dancing Clown, is the titular antagonist in Stephen King’s 1986 horror novel It. The character is an ancient, trans-dimensional malevolent entity who preys upon the children  of Derry, Maine, roughly every 27 years, using a variety of powers that include the ability of shapeshifting and manipulation of reality.

https://en.wikipedia.org/wiki/It_(character)