Kayn, The Shadow Reaper

{4}{u/b}: Exile Kayn, The Shadow Reaper then
return him to the battlefield transformed under
his owner's control. Activate only if this
permanent has dealt combat damage to a player
this turn.
{4}{b/r}: Exile Kayn, The Shadow Reaper and create Rhaast, a legendary 5/5 Horror creature token
with lifelink and indestructible. Activate only if
this permanent has dealt damage to a creature
this turn.