Fleet Footed Steed

When Fleet Footed Steed enters play, you may exile target Human or Elf you control until Fleet Footed Steed leaves the battlefield.
If Fleet Footed Steed exiled a creature this way,
it enters play as a copy of the exiled creature except it gets +1/+1, vigilance, flanking, haste,
and is a knight in addition to it's other types.
When Fleet Footed Steed leaves play, shuffle it
into its owner's library.