THAM KENCH, Limits Broken

When I flip, Devour 2. Vigilance
{t}{u/b}: Remove target creature from the game.
Give me -0/-X, where X is equal the total power
of creatures removed from play with this ability.
When I attack, return all creatures removed from
play by my ability to the field, tapped and
attacking. Then send those cards to their
respective graveyards at the end of combat.