That's a useful ability :)
Untap, upkeep
Plains
Seraph of Dawn, triggering the Tomb
Attack with the Tomb for 3
Done
Spidey: 23
Hand: 11
Battlefield:
(T,T) Plains x2
(T) Swamp
(T) Island
(T) Angel's Tomb (Whenever a creature ETB under my control, I may have ~ become a 3/3 white Angel...