Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.
Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.
Search your library for a green creature card with converted mana cost X or less, put it onto the battlefield, then shuffle your library. Shuffle Green Sun's Zenith into its owner's library.
Red Sun's Zenith deals X damage to target creature or player. If a creature dealt damage this way would die this turn, exile it instead. Shuffle Red Sun's Zenith into its owner's library.
Put X 2/2 white Cat creature tokens onto the battlefield. Shuffle White Sun's Zenith into its owner's library.