What is a glowstone impossible object?
"so, it's just that it's a sphere, and like you can place it down and stuff, but it doesn't actually do anything other than sit there and be spherical"
"It lights up? That's about it."
[source]
You're correct about it being from Extra Utilities. It's basically a sphere that emits light. The name "Impossible Object" is a reference to the fact that true spheres are impossible in Minecraft.
Below is an example of a player using Impossible Objects as ornaments for a Christmas tree.
