The Giant Arm, a type of Mutated Zombie, can use weapons, which means its combat effectiveness is completely different when it's armed versus unarmed. Naturally, the weapon's quality also affects its combat power.
According to the observers, the Giant Arm from the Industrial Park was holding a steel pillar over 10 meters long. Judging by its shape, it was likely the support strut from a small spacecraft and was incredibly hard and sturdy.
With such a "good weapon" in hand, this Giant Arm's combat power would undoubtedly rise to another level. On top of that, there was also a Spitter that could send it into a berserk state. Actually fighting it probably wouldn't be much easier than dealing with a Death Claw.
As for the last one, the Blood Worm, it was the most troublesome of the four Mutated Zombies.
This was a Mutated Zombie with a body even larger than a Death Claw's. Its stomach, in particular, was almost big enough to hold a truck.
