Wow. That was no good. Of all the answers, mountain probably made the least sense.
“I’m defeated by winter, yet all my blood runs cold,
Mountains don't have blood. And winter has nothing to do with this.
In the whole of the planet, I am the most old,
Perhaps. But the whole of the planet? Oldest? Tectonic plates, bro. Look it up.
Always running, yet never am I tired,
Mountains don't run. Mountains don't even move.
I’m not destroyed by time, nor even by harshest fire.
Well this might make some sense because Oh yeah, dynamite counts as "fire". Damn.
What am I?”
Not a mountain, compadre.
Green looks at you and giggles in an eerie way. Red still looks angry. Or maybe he's happy. You don't seem to care.
"Can I guess again?" you ask.
"Nope!" Green gleefully sings, as a portal begins to open up beside you.
Seconds before being suck in, you think