Apkallu, Sire of Dread

When you cast this spell, surveil X, where X is
the amount of mana spent to cast it minus 4.
Other Kraken, Leviathan, Octopus, and Serpent
spells you cast cost {u/b}{g/u} less to cast. This effect
reduces only the amount of coloured mana you
pay.
Krakens, Leviathans, Octopuses, and Serpents
you control have Ward — Discard a card.