The Core is one of the craziest, toughest planets you will ever encounter.
The Core Overview!

The Core - The Toughest Rescue Mission

It is shaped like a humongous apple that has had 2 bites taken out of it. But it was probably created by enormous explosions set off by the robots themselves.

There is very little shelter from the two Armored Robots and the "stem" just blocks you and gets in the way.