Tbone the Dragonborn

Reach,Trample
Whenever Tbone attacks, add {x} Mana in any combination of colors, where {x}
is the total power of attacking creatures.
spend this Mana only to cast spells.
Until end turn you don't lose this
Mana as steps and phases end.
{3}{r/g}{r/g} put a +1,+1 on any creature you control