Megatron, Tyrant

More than meets the eye {1}{r}{w}{b}(you
may cast this card converted for {1}{r}{w}{b}.)
Your opponents can't cast spells during combat.
At the beginning of your postcombat
main phase, you may convert Megatron.
If you do, add {c} for each 1 life your
opponents have lost this turn. 4/5