Trail Racer, Blade Savant

Flash, Hexproof
Whenever Trail Racer attacks or blocks, Surveil 3.
Whenever you Surveil, each opponent puts cards
from the top of their library to the graveyard
equal to the number of cards you placed
back on top of your library.
As long as you've Surveilled this turn, Trail Racer
gains "{u}{b}: Exile Trail, then return him to the battlefield at the end of the turn"