What block is this pitch black void block? NeoForge 1.21.1

[eager carbon]

Its a specific block, not an antiblock that has light. Tried that mod but it wasn't that one.

[thorny swan]

black concrete

[eager carbon]

i remember specifically that it wasnt this because im using an old video of mine as reference

and i know for a fact theres a mod somewhere that adds a specific black void block

i just cant recall