Keeper of the Crystal

{2}{u}{t} Tap target permanent creature your
opponent controls. That creature doesn't untap
during its controllers next untap step.
{2}{u}{b} Keeper of the crystal gets +0/+6 and
gains Defender until end of turn.
{1} Sacrifice Keeper of the crystal, create a
colorless Token Artifact with: "Creatures you
control have hexproof."
Nobody gets past this dude, nuf said.