When Protean Hulk dies, search your library for any number of creature cards with total mana value 6 or less, put them onto the battlefield, then shuffle.
2018-03-16
If a card in your library has {X} in its mana cost, X is considered to be 0.
2018-03-16
You can find any number of creature cards, so long as their total mana value is 6 or less. For example, you could find eight creature cards with mana value 0 and three with mana value 2, but you couldn't find two with mana value 4.