From 2speccers2tools wiki

The hijackerjacker is the result of a hijacker I that got another hijacker to do the dirty work for it. The hijackerjacker is much rounder and smaller than its ancestor and possesses long hooked claws on its legs and tail in order to latch on either its target host (its ancestor) or other machine fauna for transport. When searching for a host and a hijackerjacker encounters another machine organism, it will latch on to it and lay dormant in hopes of eventually finding a hijacker I attempting to infect its ride, otherwise hijackerjackers lay dormant floating through space. If a hijacker I is encountered, the hijackerjacker springs into life and flies over to it. It will then latch on its victim’s back end and pry open a crevice of its host to inject its myceliform into the hijacker I. Once this is done the hijackerjacker’s fuanaform promptly dies, often still latched on its host. The myceliform however gets to work and locates the Hijacker I’s myceliform and devours it, taking its place. The new myceliform avoids detection of the immune system by copying the surface of the myceliform it has just devoured. The hijacker I proceeds to do what it does as normal but instead unknowingly injects the myceliform of the hijackerjacker, which then proceeds to do all the same tricks to the host that its ancestor does. Being much smaller than its ancestor results in the machine fauna making loads more hijackerjackers than what would otherwise be possible with a hijacker I, this increases the chance of a hijackerjacker finding a host.