Ark Megaforms (негуманоиды Ковчега) are a fictional alien race from the Noon Universe created by Boris and Arkady Strugatsky. Their homeworld is Ark (Ковчег), a planet officially discovered 2160 AD in the course of "Ark Project".
Ark Megaforms are mentioned only in one book - "Space Mowgli".
No information on the appearance of Ark Megaforms has ever been recorded, although members of ER-2 group, the humans that discovered them, recall strange 600-meter-tall structures that appeared somewhere behind the mountains every time they tried to contact the Megaforms. They looked like colossal segmented (insect-like) antennas at 100-meter amplitude. No connection between these structures and Megaforms was ever confirmed.
No exact data available. It is assumed that the intellectual abilities of Megaforms surpass those of humans: megaforms were able to directly communicate with a human (Pierre "The Kid" Semyonov) and adapt his body to the harsh environment of their home planet.
No data available. Apparently, the Megaforms are a so-called "closed civilization" which avoids contact with the entire outside world; probably that was the reason why they had completely cleared ("sterilized") the whole surface of the planet from all other living organisms.
Ark Megaforms and Humans
Megaforms directly contacted ER-2 explorer group led by Gennady Komov and demanded their immediate withdrawal from the planet Ark. No other direct contact was ever recorded.
Piere Semyonov, better known under the nickname "Little One", was a son of Alexander Semyonov and Maria-Luisa Semyonova whose spaceship was shot down in 2147 by the Wanderers' guard satellite orbiting the Ark. It is unclear why Megaforms saved the boy. Later they used Pierre as their proxy in communication with the progressors visiting the planet.