Mysteries of Unexplored Worlds #13 (1959)

Dr. John Darrell and his assistant Rick Royce become the first humans to land on Mercury, only to encounter colossal insect-like creatures and mysterious appendages emerging from craters. As their ship is pulled into the planet’s depths, they realize with growing dread that Mercury itself may be a living entity—its surface a network of caverns and orifices, and the planet’s interior a vast, unknown organism.

In the quiet of a country estate, a government agent named Doherty grows suspicious when his eccentric employer, Joshua Peel, mysteriously rejuvenates after hours spent gazing through a powerful telescope aimed at a forbidden green star. As Doherty uncovers Peel’s secret connection to the star’s alien influence, he realizes the truth is far more dangerous than he imagined—and that the real battle is not for Earth, but for the mind.

In "The Perfect Lens," Professor Harold Dennis joins an iceberg patrol, where an unusual warmth and disturbance in the water lead him to realize the massive iceberg is actually a naturally formed lens that superheats the surrounding water when exposed to sunlight. As the crew prepares to detonate the iceberg, the strange phenomena vanish—leaving behind a mystery that defies explanation.