Este poderia ser "Os comedores de lótus"de Stanley G. Weinbaum?
A month after the events in "Parasite Planet", Hamilton "Ham" Hammond and Patricia Burlingame are married, and thanks to Burlingame's connections, the two have been commissioned by the Royal Society and the Smithsonian Institution to explore the night side of Venus. There they find a species of warm-blooded mobile plants with a communal intelligence that Burlingame nicknames Oscar. Oscar is very intelligent, quickly picking up English from Hammond and Burlingame.
The humans learn that the Oscar beings reproduce by releasing clear bubbles full of gaseous spores. When the bubbles burst, the spores come to rest on another Oscar being, eventually grow into another individual, and bud off. In "Parasite Planet", the vicious, night-dwelling Triops noctivivans used these bubbles to attack Hammond and Burlingame, since the spores have a soporific effect on humans.
The humans are horrified to learn that, being plants, the Oscar beings have no survival instinct. Despite their greater-than-human intelligence, the Oscar beings react with indifference when the local trioptes attack and consume them. This prompts Burlingame to name their species Lotophagi veneris – the lotus eaters of Venus. Hammond and Burlingame barely escape the trioptes themselves after exposure to the spores leaves them almost catatonic.
Está dentro "Planeta Parasita"que eles estabeleçam as criaturas cruéis.
After a time, Hammond suffers an attack of conscience, turns, and follows Burlingame south. He catches up with her in the foothills of the Eternities just before a huge doughpot traps them in a box canyon. Hammond is able to get off two shots of his flame pistol at the doughpot before the barrel shatters, reducing the thing's size but still leaving them trapped. They decide to go deeper into the box canyon, but in the darkness they are set upon by Triops noctivivans, vicious nightside-dwelling cousins of the Venusians. The trioptes drive them back toward the doughpot, dosing Burlingame with a soporific drug that renders her unconscious. Hammond is forced to make his way past the doughpot on a low, narrow shelf of rock while carrying Burlingame.
"Lotus Eaters" pode ser lido em Histórias surpreendentes, abril 1935, disponível no Internet Archive.
Encontrei minhas referências em Existe alguma história de ficção científica sobre vida extraterrestre inteligente em um planeta bloqueado pelas marés?, que encontrei através de uma pesquisa por explorador de contos de ficção científica e esposa no planeta fechado pelas marés.