deadlights

While It can take assume any shape to terrify Its prey (ex: Pennywise), Its true form is not on earth. The true form of It exists beyond the physical, in a void surrounding our universe, known as the macroverse. It's true form is described as living, insane, writhing orange light. Direct contact with the deadlights results in instant death (with the exception of Audra Phillips who entered a deep coma). The deadlights can be seen through It's eyes when It takes the form of a giant female spider which is the most accurate shape the deadlights can translate to on earth.

1. what pennywise the clown actually is. it is an orange light that mesmorizes those that are afraid. when mesmerized, IT can feed. IT wakes up every thirty years and IT feeds. It is what is behind the clown. Like Stan Uris said "I saw what was behind the clown."

2. depression

In pirate slang Deadlights means Eyes

Leaving ones job without saying one word to anyone, then kicking up a stink the day after, because no-one bothered to get you a leaving present.

a car that has one burned out headlight.

These are seemingly floating lights the deadlights are known because they are pennywises true form
Stephen kings worst monster
The deadlights float throughout the macroverse a place that engoulphs the universe basically wrapping around reality beyond space and time and all dimensions
Anyone who sees them goes insane, dies or pennywise can take possession and control them he can tear their soul and kill them it basically pulls their mind into the macroverse
And they are incomprehensible to the mind nobody can grasp them with their mind so it brakes
They also transcend and exist outside the dark tower