Arianrhod Argonwell

{w}{r}{x}: Arianrhod Argonwell gets +X/+0 until
either the next time it deals damage or the
beginning of your end step, or it gets +0/+X
until the beginning of your end step.
{3}{w}{t}: All creatures you control are regenerated
and gain indestructible until your next turn. After
using this ability, if damage would be dealt to
Arianrhod Argonwell, prevent that damage and
instead add that many -1/-1 counters to it.