If Superman uses the power of a blue sun to bestow superpowers on another person, is that a taxable asset transfer?  Who would want to try to collect?

If two superheroes marry, share a power, then later divorce, could one be forced to give up the power during the division of assets?  Does it matter who had the power originally?  Even though the shared power may be a non-rival good, one of the two superheroes may still have a claim to exclusivity.  Perhaps the power is a trademark ability of one character, or maybe they signed a superhero pre-nuptial agreement that determined the disposition of any shared abilities.

If one superhero lends a power to another (or to a normal person), does that superhero have an implied right to its return?  In other words, is a bailment created?  I think the answer here is yes.