I heard this expression (gas killing animal) on TV news, when they reported that Trump referred to Esad(syrian leader) like this in a tweet, because Esad was reported to have used a chemical gas and killed people.
Grammatically, the phrase "Gas killing animal" did not sound natural or good English to me. If I had not known about the happenings, I would have hesitated about the meaning of the structure "gas killing animal". The structure may be confusing e.g. who is killing who? Is it the animal that kills? or is it the gas that kills an animal? etc...
If we accept this structrue correct English, can I say "water killing man" if I want o refer to a man who killed another man by using water? Or can I say "medicine killing man" if I want o refer to a man who killed another man by using medicine or pills?
So, it does not sound natural to me or it somehow sounds unusual or improper English. I do not why but it just does not sound good english.
Do you feel the same and if yes, is there any other way to put it in a clearer structure where it would not cause any such confusion?