Dreadswamp Hydra

As an additional cost to cast Dreadswamp Hydra, sacrifice a creature with mana value 3 or less.
Sacrifice a Swamp: Untap target creature with
mana value 3 or less.
{2}{b}{b}: Target creature with mana value 3 or
less blocks Dreadswamp Hydra this turn if able.
If that creature dies this turn, put a +1/+1
counter on Dreadswamp Hydra.