Idunn

{4}{w/b}{w/b}{w/b}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Idunn becomes Monstrous, she gains
Flying and Double Strike.
"A dragon of light that became enveloped in shadow,
and then brought back to the light. How unusual."