The Hivemind

When The Hivemind takes damage, if it is still
alive, heal it to full health.
{2}{b}{g}: Inflict Mind-Numbing Nova after two
turns to all creatures target opponent controls.
That player may interrupt this effect by directly attacking you.
{3}{b}{b}: Use Echoing Void, causing each creature
to die if tapped at the beginning of your next
upkeep. After that, the void echoes, causing each
tapped creature to die at the end of the
next turn.