The Small Bears by Gene L. Henderson - The aliens looked cute as Koalas. But there was a little matter of a graveyard of dead space-ships.

Billowy white clouds hid the entire surface of the mystery planet and the space-cruiser cautiously searched, seeking an opening. A wind disturbance momentarily split the misty blanket and like an arrow the ship darted through.

The sudden movement had caught some of the men unprepared and Dr. Dick Boyette hurried past fully-manned battle stations to answer a call from the control-room. It required but a couple of minutes to revive a technician who had stumbled into a panel and afterward Boyette stood in the background, watching.

Everywhere, as far as the eye could see, the terrain was dotted by patches of woods and green meadows. The perpetual cloud blanket was two miles high, thin enough so that it barely diffused the sunlight. Enough, Boyette thought, so that the planet would have been a mystery even without the disappearance of all ships that had visited it.

"No sign of life," growled Commander Kellews, breaking the silence.

"I don't like it," the gunnery officer added uneasily. "There must be life or what could have happened to all the other ships that vanished here?"

"That's what we're here to find out," said Commander Kellews. He gazed around with a fighting man's pride in the finest weapons that Earth science had been able to devise. This one ship itself could destroy the entire planet that lay so peacefully beneath them.

As Boyette knew, the mystery planet was necessary for further expansion from the solar system, lying as it did between their system and the nearest one. Yet, it had swallowed all ships that had landed.

"Look!" shouted the lookout, "that plateau's covered with ships."