The poisonous mist was Jörmungandr's trump card. Creatures that inhaled it appeared no different from usual on the surface, but the damage within them became severe. Their strength would steadily drain away under the toxin's corrosion until they died, and the stronger the creature, the shorter that process would be.
It was a deadly poison capable of reducing gods to mortals!
In Thor's battle with Jörmungandr, he had inhaled too much poisonous mist. After killing Jörmungandr, he lost his own life as well. As for the sperm whale on the second level of the platform, after Jörmungandr dragged it from the deep sea onto land, it remained conscious but was unable to resist, forced to watch helplessly as it became dinner for the swarm of snakes.
In Jörmungandr's eyes, Zhang Heng's fate after inhaling the poisonous mist should have been similar to that sperm whale's. He should soon have clearly felt his strength draining from his body, growing weaker and weaker, just like... Jörmungandr was now.
At first, Jörmungandr had not thought much of it. Its poisonous mist was normally stored in a venom sac in its abdomen and could basically only be released once a month. However, it had just used it once while hunting that sperm whale. It was not because the whale had been difficult to deal with, but because it needed the poisonous mist to soften the whale's body enough for the snake swarm to feed on it. At the same time, the lethal toxins it injected into the sperm whale were also excellent nourishment for the snakes, as irresistible to them as catnip was to cats.
Jörmungandr had already used up this month's supply of poisonous mist on the sperm whale, which was why it had relied on its body to deal with Zhang Heng