Brains!
Knowing it's what you need, you reach out for the head and your hands close slowly on it. Before you can do anything, however, it pulls back into the space behind the moving wall and you see your hands being smacked away with something hard. Then the light is gone and the wall is solid again.
The feeling inside you lurched in anger. The thing you need just got away. You have to have it. There is nothing more important than it. You bang your arms against it again and let out a strange groan. "ARRGHHGHH"
The others around you stop for a moment and look at your direction. Some of them start to move towards you as you go back to banging on the wall. The others crowd around you and start banging and scratching on the wall as well. They too must want what is inside.
You can hear the sound of something breaking off to the side and the call of one of the others from around the side, where the squares of light were. Some of them move towards the sound, while the rest still beat on the wall with you.
There is another sound of more breaking and then some heavy thuds that almost sound like they are from inside. Where you want to be. Where you need to be.
Slowly the wall seems to move slightly as you and your others continue to bang on it. The noises inside seem to continue as you make the wall start to give.
There is another groan from the other side this time as another sound of breaking rings in the air. More of your help moves that way and leave you alone with four others to keep working on the wall, as small shots of light seem to appear for the moment with each pound. Although it seems that it isn't moving any more that it has been, since your help moved off.
As the groans grow more common to the sides you begin to wonder if you should move to one of them. Perhaps they are calling because they got in, but then you only called when you failed so perhaps the same is happening to them.
All you know is you need to get inside. You need to get to that living thing in there. You have to have what is inside it.