i've noticed a few obscure drugs references in the show
1. when Moe says he got "intoxicated on cough syrup while he was in the army" This could actually be true, some cough syrups that contains only Dextromethorphan Hbr (an anti-tussive) can be used to get wasted.
2. When Homer licks those toads, it ain't anything invented. Some kind of toads produces a venom which contains 5-meo-DMT, a strong hallucinogen, which is also found in multiple plants. people squeezes those frogs though instead of licking them (that's kinda a cruel way to get stoned actually)
Are some of the writers drug users of any kind ? hehe