Warning: The following contains spoilers for Alien #4 by Phillip Kennedy Johnson, Salvador Larroca, Guru-eFX and VC's Clayton Cowles, on sale now.
The latest issue of Alien sees Gabriel Cruz, who has been searching for his son Danny in the wake of a Xenomorph attack, find finally find him, but not in the way he wanted. Unfortunately for Danny, he's been strung up in a Xenomorph nest with a Face-Hugger securely attached to his face implanting him with an alien egg that will eventually burst from his chest. They're able to pull Danny free from the nest just in the nick of time before a group of angry aliens shows up to deal with the intruders in their nest.
Gabriel and the team are able to break Danny loose and escape with him, but the Xenomorphs won't be far behind. In this issue, Bishop mentions an ability the Xenomorphs possess that allows them to track their embryos like a homing beacon. This means as long as Danny is infected with a Chest-Burster, he and anyone who's with him can be tracked by Xenomorphs where ever they go. This idea is probably familiar to Alien fans because it puts a devilish spin on the idea of Ripley tracking the aliens from the original movie. This was one of the few advantages the humans ever had over the Xenomorphs, and it helped Ripley stay alive.
Gabriel contemplated killing his son once he sees him trapped in an alien nest with a Face-Hugger wrapped around his neck. But he's stopped by Danny's girlfriend, who convinces him to rescue Danny instead. After freeing Danny, they are ambushed by a trio of Xenomorphs. Gabriel manages to kill one with his sidearm before escaping. This is when we see the Xenomorphs study their nest and notice one of their human incubators is missing, so they go looking for him. The Xenomorphs lock onto Danny's embryo's biological signal quickly and move to cut off their escape route.
Gabriel and the group make a mad dash towards the loading dock with Xenomorphs in close pursuit. Before they can lock one of the doors behind them, Bishop gets sliced open by a lunging Xenomorph before Hamilton could gun it down. Once they reach the docking bay, Hamilton goes to disengage the second airlock and when he does there is a grinning Xenomporph waiting for him.
This new tracking ability is just another reason why Xenomorphs are the most terrifying creature in the galaxy. It's bad enough when a Xenomorph snatches your loved one and turns them into an incubator for their younglings. It's even worse when conducting a rescue mission could mean leading the Xenomorphs right back to your base of operations. That's why this ability is so scary, because it makes rescuing infected victims a potential suicide mission for not just the rescue party, but anyone that comes near the infected.
In Gabriel's case, the rash decision to rescue his son got Hamilton killed and led the Alpha Xenomorph directly to them in the docking bay. Even if they escape the Alpha, they still have to remove the Chest-Burster from Danny's body somehow or the rescue attempt will end up costing many more lives than it saved.