Fastest way for an invincible immortal to make $1 billion USD? Tags: immortality super-powers economy? biology? So, I gave a $100 bill to a homeless person a few months ago who gave me "God's blessings" in return. Apparently, that conveyed immortality and invincibility on me as I no longer age (I think) and cannot be injured. Think Superman-style iron skin, except I haven't found my krypton…