Nostalgic Alien fans pining for a taste of the original film’s blood and gore were presented with a gruesome gift on Christmas Day: a new trailer for Alien: Covenant, in which a baby alien rips its way out of a man’s back. It was a sign that Alien’s aliens are getting stronger: While the original film’s creature exited through a human’s tender gut, the new alien is seemingly strong enough to break through a fully grown man’s spine.

A human spine is incredibly rigid and difficult to sever — especially so because its 33 interlocking vertebrae are attached to some of the core’s toughest muscles and bones. For the alien in Covenant, breaking through a man’s back would not only mean cracking the vertebrae, tearing the cartilage between them, and ripping through the muscle encasing the spinal column; it would also mean detaching the vertebrae from the back muscles to which they are anchored to, as well as wrenching them from the ligaments joining them to the ribcage and the pelvis.

In a video explaining the amount of force that Mortal Kombat’s Sub-Zero requires to pull off his signature spine-ripping finishing move, YouTube science guru Vsauce3 calculates that some 5,000 Newtons of force would be required to pull out a person’s backbone by yanking upwards on their head. His simulation showed that even this much force wouldn’t break the spine completely; because the spine is so stubbornly anchored to the other parts of the body, only eight out of the vertebrae came out with the head in the simulation, while the rest stayed intact.

The latissimus dorsi is the back's largest muscle, anchoring the spine in place.

Of course, Covenant’s alien does not attempt Sub-Zero’s move by popping out through the man’s head. Instead, it breaks through the spine — and perhaps even the ribcage — from within. In particular, it appears that the alien breaks through the thoracic (chest) vertebrae, right down the middle of the torso. Doing this would arguably require even more strength than the Mortal Kombat finishing step, and harnessing the speed required to attain the amount of force needed to break through the body’s bones, muscle, and flesh would be especially difficult, given how little room there is to build momentum inside a human torso.

But, as Bruce Lee’s infamous one-inch punch famously illustrated, it is possible to produce a tremendous amount of force given a very small amount of space. What’s key is the ability to generate the velocity needed to drive that force, which is itself a factor of an individual’s strength.

By breaking through all of the back’s protective layers, the Covenant alien puts the original alien — who opted to take the easy, defenseless ventral route — to shame. Whether the same can be said for the film itself, however, remains to be seen. Fans will find out on May 19, 2017.