Glongulg, Murk Mugger

When Glongulg attacks each opponent reveals
the top two cards of their library then adds one
of the cards they revealed this way to their hand
and exile the other with a drown counter.
You may play lands and cast spells from among
cards exiled that have drown counters on them,
and you may spend mana as though it were mana
of any color to cast those spells.