Delighted Halfling

{t}: Add {c}.
{t}: Add one mana of any color. Spend this
mana only to cast a legendary spell, and that
spell can’t be countered

"I was trying to get Pip's attention to warn her
that the dangerous outlaw Cheery Ollie, who also goes by just 'O', was headed her way. "Pip! Pip! Cheery O!", I shouted."