IT vs Nightmare on Elm Street

Connection:

Both are iconic horror movie characters who invade people's dreams and turns your greatest fears into reality, often doing so in the same location they've originated from (Derry and Springwood respectively). They also devour the souls of their victims

Both are known to prey on children

Both are also known to be able to comeback albeit in different circumstances (Pennywise returns every 27 years and Freddy can return as long as the people of Springwood remember his name)