Sky Cell

When Sky Cell enters the battlefield, put a Sky
counter on target creature.
As long as you control Sky Cells, creatures with
Sky counters on them are Prisoners in addition to
their other types. They gain "This creature can't attack or block.", and "{t}Sacrifice this creature."
They lose all other abilities.
{3}{w}: Create a token copy of this enchantment. Activate only as a sorcery.