The great Carsonization:

The elderly priest gazes down upon the baby, tiredly excited. This day has been generations in the making. Centuries of cajoling and coercing had gone into this moment.

Lifting the child and turning toward the crowd below the battlements, he proclaims "It is time!". The crowd erupts into applause, roaring their approval. With this naming ceremony/funeral, every last person on the planet is now named Carson.

Everyone erupts from their skins and becomes crabs. The end