I'll go first:
Weirdest anime I've ever seen is Classicaloid, an anime about artificial clones of famous classical composers called Classicaloids who can do crazy shit like summon giant mechs with their music. Beethoven has a weird obsession with making gyoza dumplings, Mozart's a femboy, Chopin's pretty much agoraphobic, Liszt looks like a MILF now, Tchaikovsky's also an anime girl, and Shubert's entire character is constantly shouting "BEETHOVEN-SENPAI!!!!!".
And that's barely scratching the surface of this treasure trove of pure madness. But don't take my word for it, go experience this absolute chaos for yourself