Kieran, Reckless Knight

Dash {r}{r}
When Kieran, Reckless Knight enters the
battlefield, if you cast it for its Dash cost,
creatures you control get +3/+0, trample, and
"If this creature attacked this turn, sacrifice it."
{w},{t}: Sacrifice Kieran, Reckless Knight.
Creatures you control gain indestructible
until end of turn.