Cactus Game Design Message Boards

Yes.

Here's a Brass Serpent that's beheaded:   

To add a little more explanation.

I think in the same phase you can use that to heal all heroes but if you play beheaded first in your upkeep then discard phase then I don't think you could use BS to heal both.

False. Heal cards that target multiple heroes (such as Brass Serpent or The New Covenant), when played, will heal all legally-targeted heroes that were discarded during that turn. So if your opponent for whatever reason plays Christian Martyr on your hero in the prep phase and uses Haman's Plot in the battle phase, you can use Brass Serpent to heal all four heroes that would have been discarded, since they were discarded in the same turn.