Plastoid

(Daredevil I#49 (fb) - BTS) - Robotics expert Starr Saxon developed a robot assassin -- the Plastoid -- that could track its target with its sense of smell, and also equipped it with the ability to increase its size and power for a limited time in emergencies.

(Daredevil I#49 (fb)) - "Some weeks ago," Saxon went to a prison visiting area and met with mobster Biggie Benson. Benson hired Saxon to send his robot against Daredevil as revenge for the hero's interference in Benson's attempted framing of ex-police officer Willie Lincoln (@ Daredevil I#47). Eager to test his creation, Saxon returned to his lab and programmed the robot with Daredevil's "aromagraph," then sent it out to pursue its prey.

(Daredevil I#49 (fb) - BTS) - The Plastoid tracked Daredevil to Matt Murdock's apartment -- it dropped off a small tracer unit (see comments) and hid in a closet.

(Daredevil I#49) - When Murdock returned home, he heard the sound of moving gears coming from the closet. As he opened the closet door, the Plastoid burst forth and struck Murdock repeatedly, knocking him out. The robot carried the unconscious Murdock out to the street to return to Saxon's lab, but it detected the sound of an approaching passerby -- not programmed to deal with this contingency, the Plastoid dropped Murdock and fled.

The passerby turned out to be Willie Lincoln, who treated Murdock's injuries. Afterwards, Murdock (sure that the robot would return to finish its job), went back to his home and changed into his Daredevil costume (which he had greased) and waited in the private gym area of his apartment. The Plastoid returned and smashed through the wall. During the short skirmish, the hero's greased costume made it difficult for the robot to get a grip on him. The Plastoid eventually struck Daredevil and stunned him, then it wrapped him up in a gym floor mat to get ahold of him...

(Daredevil I#50) - Daredevil managed to shoot a cable from his billy club and pull himself free just before the robot hurled the mat against a wall. After Daredevil eluded several more strikes from the Plastoid, the robot calculated that since it couldn't defeat its foe in its present form, it had to resort to switching to ultimate power. Growing to giant-size, the Plastoid pinned Daredevil to the floor, but the hero slipped from its grasp. The Plastoid next tried to run into Daredevil and pin him against a wall, but the hero swung out of the way before the robot hit. The Plastoid's internal circuitry was damaged by the impact, making it unable to recall its mission; returning to the street, the robot headed back to Saxon's lab for repair, with Daredevil following.

The Plastoid reached the lab and stood before Saxon just as Daredevil entered. The robot's creator had a short struggle with the hero, then Saxon attempted to reprogram the Plastoid with Daredevil's "aromagraph" in the "aromascope," but in his haste, he accidentally reprogrammed it with Biggie Benson's "aromagraph" instead. With its new target input into its system, the Plastoid swatted Daredevil aside and headed to the prison, but it left an easy trail for the dazed hero to follow.

Smashing through the prison wall, the Plastoid easily shrugged off the prison guards' gunfire, although Daredevil received a flesh wound when he strayed into the line of fire. Daredevil made his way ahead of the robot to Benson's cell. As he tried to warn him about the approaching danger, Benson clubbed him with his fist and knocked the wounded hero out. Then the giant Plastoid crashed into Benson's cell...

(Daredevil I#51) - The Plastoid seized Benson just as the guards rushed in with a Stun-ulator. Sensing danger and determining its first priority was to protect itself, the robot dropped Benson and increased its size even more. The guards blasted the gargantuan Plastoid with the Stunulator, which caused a reaction in it akin to human pain. The Plastoid collapsed and fell on top of Biggie Benson, killing him -- with Benson dead, the robot considered its mission accomplished and it switched itself off.

Later, Saxon tried to detonate the robot from afar, but Daredevil used his radar sense to locate the destruct mechanism, which he deactivated by striking.