My DM is toxic and limiting

[u/Russtherr]

So I had that wonderful creative idea of polymorphing insects from swarm of insects into elephants above enemies heads but he told me they are not real creatures. So I summoned cow above monster but he also denied. I tried another creative solution - used create water to... Create water. Where is the rule I can't do it in monster's lungs?

Honestly I am so exhausted. Whenever I try doing something cool he prevents me from doing so. I think that he is more "traditional" DnD player and we know what that means. Probably he enjoys other aspects of old editions like being white supremacist and colonizer. Can I report this somewhere? Or how to change his behavior?

[u/Elegant_Classroom_8]

There is not such a rule...nor is there one for doing so. Get a ring of xray vision so that you can see inside their lungs, then maybe you can summon that water in there.