Green Things in My Fandoms

The prompt is "green" so I'm just going to brainstrom some green things in fandom.

Green is the colour of Slytherin. It's the house of those cunning folks who use any means to achieve their ends.

Harry Potter has green eyes. It is said that Harry has his mother's eyes. Rowling said if they were casting Lily, there needed to be a resemblance (in the eyes) but they don't absolutely have to be green.

The killing curse Avada Kedavra produces green light. On a side note, when writing this, I suddenly want to do flame test experiment and create green flame. I will ask my mother later. She's a chemistry teacher by the way.

House Tyrell has golden rose on green field as their sigil. They rule the Reach, the most fertile region and thus, the greenest part of Westeros.

There is a song by Panic! At The Disco called That Green Gentleman. I like the lyrics, "Things have changed for me and that's okay, I feel the same, I'm on my way." What I don't understand is the title. Why is the gentleman green? Why is the song given that title? Who wrote the lyrics and who gave the title? What did he think when he pick the title? Then I realise that the only sensible answer is, "Because it's a song by Panic! At The Disco."

I realise that I can't find any green thing related to My Chemical Romance. Well, Gerard Way hasn't dyed his hair green, has he?