Click see inside to see this glitched block. I've ran into this glitch a few times, but never bothered to share the glitched block with anyone. The block goes back to normal when you put something in the dark input.
Please don't report this, the block functions exactly the same as if it weren't glitched (the only difference is that you can't type anything into the dark input) I did not hack this, this just happened to me while I was coding (in a very very large sprite that has over 17,000 blocks)