A new creature?

First of all, Hi everyone. I finnaly joined you guys. I am a fan of Alien, Predators , Prometheus movies. Sorry if this was discused allready. I've seen something that botters me in Prometheus: when the Deacon get out right next to him, on the floor, is a "ball" (dont know how to describe, sorry if my english is bad) that looks pretty much alive to me.... You can hear in the background the hearthbeats (you can be tricked that is the Deacon's hearthbeat) and if you watch carefully, you can see that the "ball" is pumping in that rithm. So i am only thinking that it's some kind of a new "alien". It doesnt have sense to me that the Deacon's heart should be outside his body...Hell, no.