As the name suggested, it's a One Way Barrier Block, it's a very simple mod which allows any entity to walk through all side beside the front side. The block can be found in Functional Tab
-Why was it created?
This mod was created as an intention for a minigame where mobs will spawn into the arena but not allowing the player to leave the arena.
-Where I got the idea from?
The mod is inspired by CS:GO wrong way tools in Hammer as a way to show to players that entrance you cant enter. But I put my twist by allowing any entities to walk through from any side but the front.
