Axel, Stalwart Guardian

When Axel, Stalwart Defender enters the battlefield, you may sacrifice an Artifact. If
you do, it gains +0/+2 and has Vigilance.
{t}: Target creature you control gains
Hexproof until end of turn.
"This isn't some high school field trip. You're
here to kill them, and I'm here to make sure
they don't kill you."