Ok, I'm gonna post all the possible arena events that I come across.

This is gonna be interesting....

Event:  Perpetual Darkness

Event:  Tsunami

Lol, Peppy won again.  XD

Event:  Volcano

Event:  Fire

Event:  Acidic Rain

Event:  Carnivorous Squirrels

That's all I've found so far.  I'ma go to bed now.  Or play Minecraft.  One of those.  XD

~~~~~~~~~~~

I found some more!

Event:  Tracker Jackers

Event:  Border Contraction

Deana is another one of my friends, btw.  XD

Event:  Poison Cloud

Event:  Monkey...Mutts?

I don't get that last one.  XD