The sea squirt is a strange creature. It seems to be a backward oriented creature. The juvenile sea squirt wanders through the sea searching for a suitable rock or hunk of coral to cling to and make its home for life. When it finds its spot and takes root, it somehow figures it doesn't need a brain anymore. So it eats it.

The analogy between the sea squirt and some tenured professors has been pointed out on numerous occasions—but the church ought not laugh too loudly. It does the same thing. It finds a home and then settles in. When this happens, it enters what is known as a PVS—persistent vegetative state. That is, it eats its brain.  The church grows inward, no longer following its God-given mission.

Someone has criticized the ingrown church with these words: Today, we in the church speak and act on little but that which relates to ourselves. We refuse to learn the language of the culture. We are reluctant to trust the Spirit already at work in the world. What is born out of this retreat is a kind of indoor spirit that does for the body of Christ what an ingrown toenail can do to the human body: It becomes diseased and infected and is a danger to the whole organism. An ingrown spirit can ground a body [local church] just as much as an ingrown toenail.

Jesus ran into this self-centered attitude among the religious people of his day. It caused him to confront them with a series of parables in Luke 15.