can cone of flame deal 6 damage to a single creature or player?
can cone of flame deal 6 damage to a single creature or player?
No. Each of the targets must be a different creature or player. This is reflected in the Gatherer rulings entry for Cone of Flame:
As it says, you can't even cast it if you don't have exactly three different targets for it.7/15/2007: You can't choose the same target more than once. If there aren't three different legal targets available, you can't cast the spell.
can I choose to deal the one damage to myself or one of my creatures and the rest to the enemy creatures?
Yes.