Murph, the Steadfast

Invincible (This creature cannot be affected by
any card your opponent plays while it is in any zone.)
At the end of your turn, if you control five or
more creatures, sacrifice Murph, the Steadfast.
"Dogs die. But dogs live, too. Right up until they die,
they live. They live brave, beautiful lives. They protect
their families. And love us. And make our lives a little
brighter. And they don't waste time being afraid of
tomorrow."