Shinokuni

Shinokuni (シノクニ) is a chemical weapon created by mixing compressed H2S gas with a candy containing an unknown substance.

History
When Caesar decided to debut his newest gas weapon to brokers across the world, he lured Smiley with a piece of "bait" in the shape of a giant candy, which, when devoured, had Smiley regress back into his original gas form, with the bait's ingredients converting the H2S gas compound into an even deadlier form, decimating many of Caesar's centaur subordinates.