Cat Shelter

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

This creature must be blocked by exactly one creature if able. Whenever this creature attacks, create X tokens that are copies of it and that are tapped and attacking, where X is the number of creatures defending player controls. Exile the tokens at the beginning of the next end step.