Every Hidden Pennywise From IT Chapter 1 & 2
12. Ben's Library Research - It
There are actually TWO Pennywise moments in the library sequence. The first is not It in his clown form, but rather he's assumed the image of the librarian.
As Ben flips through A History Of Old Derry and the images change to zoom in on the head of a dead child thrown up into a tree, we watch Ben grow more and more frightened. As that happens in the foreground, the background shows the librarian turn in his direction, hunch strangely and her expression changes into a maniacal smile. Clearly, we're watching It in disguise enjoying Ben's fear.
In the same sequence, as Ben's flipping through the book, there's a shot of the Derry Easter Egg hunt and a group of children posed. Right at the top right of the image, there's a blurred shot of Pennywise stalking his prey.