there's a few blocks in Minecraft that seem useless but have one random thing like the End Rod it looks cool but does nothing except if you place it like this you can get through but mobs can't and even creepers will die next is sand normally TNT explosions won't do anything underwater but by putting sand above it it can explode really useful for Ocean Monuments then mushrooms but specifically these giant mushrooms for some reason by placing one right here you can break the end frame finally the shulker which is obviously super useful for storage but not
as a block but if it's in a three-high room with no block under it you can get on top and to open it to phase through