Due to Sword Pill's explosion, there was too much matter that was in a state of superposition of intangibility and corporeality. It magnified the sensations Zhou Wen experienced by a thousand times, causing his body and mind to be affected.
Zhou Wen clearly sensed the existence of the smoke. No, it shouldn't be said that it was smoke, but a type of particle. A particle that Zhou Wen had never seen before. The characteristics of this particle were very strange. It had two sides like Yin and Yang. When it switched to Yang, it would exhibit the characteristics of a corporeal object. And when it switched to Yin, it would exhibit the characteristics of an intangible object.
Zhou Wen could only previously sense its Yang aspects, but not the Yin aspect. He finally sensed the Yin aspect due to the intense effects of Sword Pill's explosion.