How to become space junk real quick: assume the human standard of death is the only standard, and miss the three big Earth-climate clues to the mistake you are about to make.
Winter comes on Earth because of the oscillation of Earth on its axis, tipping one hemisphere at a time away from the Sun. On planets with no such oscillation, winter is sometimes determined by pulsations of variable stars or stellar storm periods. In star systems that have none of that going on, planets that do not oscillate can still have seasonal changes depending on the irregularity of their orbits, and thus can still have winters.
All that said, planets that do not oscillate on their axis and have stable orbits close to stable stars should not have winter – there is nothing that should cause that level of cooling.
The first thing one ought to do before picking up anything off a planet that has unexplained climate is to determine why the planet behaves that way. That was Clue 1, and it was completely missed.
Clue 2: many creatures on Earth go into hibernation or dormancy in the winter to rest. Animals do this in covered, safe locations, and deciduous trees and their saplings do it in the open … so you could think that a large figure growing up through the snow might be some kind of living dormant being.
But all this particularly hapless artifact hunting team saw were complex, beautiful skulls sitting up in the frozen soil, and assumed they were dead because generally, skulls are dead.
In reality, the above figure was more akin to a dormant tree, if you account for the planet's trees controlling the planet's seasons entirely. The seasons literally followed the waking and dormancy pattern of its plants; they pumped heat energy directly from the core of the planet and shut down the pumping so they could rest.
Guess what happens when you pile a few dozen such beings together, and they think because of the warmth of the cargo hold – because of course the men turned the heat up because of how chilled they were upon coming in – that their fellows had begun the yearly beginning of the pumping?
Guess what happens when such beings mistake your ship's power banks for the core energy of their planet and don't know or care about the containment field of your warp core, just as you are going to warp?
We know what happened because the cycle of the planet and a reenactment of what had occurred on that ship had revealed the most likely answer.
If you must collect skulls for profit, you must first be sure they are dead and not running the climate of a whole planet, because otherwise, there may not be enough of your skull left for anyone to collect.
This is a different variant on the fractal in Apophysis 2.09 that gave us Mr. Oahuapedal yesterday, the first in the same palette ... very much resembling some kind of alien compound skull ... but then I thought, "What if that thing were alive?" and changed the palette to reveal its hidden powers!