as we all know aliens colonial marines is out and the orgins of the mysterious mutated juggernaut we know as the crusher is shrouded in mystery but I may have the answer

You all know the basic cycle of a drone to praetorion with the. but what about the runner does it have a smiliar cycle lets say we have a runner from a dog facehugged then it grows from chest burster to full size. like the from alien 3 it has a dome shaped skull  it also behaves like one too because in alien 3 the runner mainly stayed away attacking if it absolutely had to take for example the part when it killed the warden it immedietly ran off in the vents because it could would surely die in because there were to many humans so it used stealth tactics picking them off one by one just like the Nostromo drone it also took them in vents for when the queen in Ripley was fully grown another ability it shares with drones is spitting acid and secreting hive webbing. If it had been given more time it would have gotten bigger to warrior size then if possible a crusher because of the massive headcrest,size and durability. to make it easier

facehugger+dog=runner+molt=warrior+royal jelly=crusher praetorion