History:
(Captain America I#187 (fb) - BTS) - Under unrevealed circumstances, the Druid apparently transformed one of his lackeys into the Alchemoid, a walking storehouse of alchemical energy -- the Alchemoid was to be the prototype for an army of similar beings, which the Druid would use to defeat S.H.I.E.L.D. and conquer the world for himself and his followers. The Druid stationed the Alchemoid in the center of the Maze of the Ancients.

(Captain America I#187) - Utilizing one of his flying Satan's Eggs, the Druid kidnapped Captain America and transported him to a mountainous region, then deposited the hero into the Maze of the Ancients, where he intended to destroy Cap within the labyrinth as a prelude to the destruction of S.H.I.E.L.D.

   Captain America made his way through the maze, battling past "sulphuric creatures" and "robotic flying eggs," and avoiding deathtraps; as he neared the center of the maze, Cap finally confronted the Druid himself, but the Druid sent his creation -- the Alchemoid -- to battle him.

(Captain America I#188) - Fighting face-to-face, the Alchemoid threw a punch that sent the hero flying, proving himself to be stronger than Captain America, and the oily ooze of his touch burned through Cap's glove. But during their battle, Captain America noticed that the Alchemoid became stronger when he stood near some geometric sculptures in the maze's center -- he correctly figured that the polyhedrons acted as external boosters for the Alchemoid's power; with that in mind, Cap tricked the Alchemoid into blasting some of these polyhedrons.

   Understanding that Captain America was manipulating the Alchemoid into destroying his own power feed stations, the Druid ordered his monstrous servant to immediately slay the hero, then turned a dial that augmented the power channeled into the Alchemoid. However, the sudden and excessive burst of power was too much for the Alchemoid to handle, and he overloaded and exploded.

   Angered by the Druid's lack of concern over the death of the man who had been the Alchemoid (see comments), Captain America turned his attention to battling the villain and the rest of his underlings; but the Druid managed to escape when Eric Koenig and the forces of S.H.I.E.L.D. arrived to capture his henchmen.

   The colors of the Alchemoid's suit and skin changed from Captain America I#187 to Captain America I#188 (both on cover and in story) -- maybe it depended on the heat he generated? The acidic oil produced? The energy level raised? Or the colorist?

   Although the Dredmund the Druid profile in Mystic Arcana: The Book of Marvel Magic described the Alchemoid as an android, he actually seemed to be a mutated costumed human -- unlike the other silent artificial creatures Captain America faced, the Alchemoid spoke and used contractions (e.g. I'm, you're, can't, etc.), and he reacted in pain and anger when struck by Captain America's shield; also, after the Alchemoid exploded, Cap described him as "a man".
--Ron Fredricks

A labyrinth hidden somewhere in a mountainous region of upstate New York, it was where the Druid made his base.

The maze's "stone" walls were actually made of wood covered by a thin layer of cement, and some of the walls moved to shift the maze's configuration, to further confuse anyone trapped inside.

At the center of the maze was the Arena of Ages, which had sculptures of geometric shapes (e.g. pyramids, spheres, cubes, and various polyhedrons) -- these were actually disguised power feed stations that transmitted energy to the Alchemoid.

After making his way past the artificial creatures and deathtraps of the maze, Captain America got to the Arena of Ages, where he faced the Alchemoid in battle.

--Captain America I#187 (187, 188

This trio of artificial creatures were stationed inside the Druid's Maze of the Ancients.

While Captain America was making his way through the maze, he encountered the three creatures; because they strongly reeked of some kind of sulphuric compound in their bodies, Cap assumed they were artificial, so he didn't restrain himself when he fought them (I guess it never occurred to Cap that they might just be three guys with poor personal hygiene).

But when he struck one, Captain America's hand bounced off, and he thought the creatures to be "walking sponges" with mass and weight.

When the creatures had him boxed into a dead end of the maze, Cap slashed at one with the edge of his shield and sliced it in half, rendering it inert; Cap apparently dealt with the remaining two in a similar manner, then continued his way through the maze.

(Comment: These creatures reminded me of the Leader's Humanoids;  and according to the spellcheck and my old-fashioned dictionary, the preferred spelling is "sulfuric," but this is the way it was spelled in the story.)

--Captain America I#187

Probably based on the technology of the Druid's flying Satan's Eggs, these three small automatons were stationed inside the Maze of the Ancients. They each had two flexible tentacle-like appendages, and could discharge some form of energy beams.

Captain America was easily able to defeat them --he used his shield to smash two of the robots, then grabbed the third by its arm and swung it to batter down the fake "stone" walls of the labyrinth, until he reached the center of the maze.

--Captain America I#187