entity_blocker
entity_blocker
is a point entity available in all Source games. This is spawned in temporarily to prevent NPCs from pathfinding into spaces like spawn points or movement targets. It's an invisible box solid to certain other objects. Some entities create this automatically in order to keep a certain area clear of things that could block their movement. The entity can be replaced by a simple clip brush. It does not have any unique I/O or properties with spawnflags.