1. It's a German model Tenor horn. Plays and sounds like a baritone or Euphonium
2. We're not allowed to talk about the big hand
3. If you look closely though the jpeg artifacts you can see that they are hooked up near the floor. They are functioning urinals.

1. Something in the Saxhorn family I would guess. Possibly a marching euphonium?

2. It was the same day as those thwack tubes, you missed a really fun day.

3. They do look plumbed as urinals to me, it’s just really hard to see the drain pipe going off to the right of each bell behind the bells.

you don't know about the big scary monster hand?? lol imagine not knowing about the big scary monster hand. super important.

To me, that looks like a baritone with rotary valves as opposed to piston type valves. It seems like the right size, and the piping is cylindrical, as opposed to conical.

Doesn't look exactly right to me, but it might be a Wagner tuba?

Whoever is cleaning that will probably not blow their own horn about it.