Plant People Pester Planetary Protectors

Bur Sed and his son Ker Sed were self-appointed "Keepers of the Balance", who traveled to various worlds attempt to return the worlds they visited to ecological balance. Their terraforming of Earth-One was opposed by members of the Justice League, including Superman, Batman, Flash, Green Lantern, Aquaman, Black Canary, Atom and Hawkman.

King Tassel and his lieutenant Lord Cob were the rulers of the planetary moon known as Rykornia, which sought to usurp control over worlds they visited. Their terraforming of Earth-Two was opposed by Justice Society member Wonder Woman, along with her friend Etta Candy and the other Holliday Girls of Holliday College.

Each Dastardly Duo was armed with powerfully potent seeds, which they spread across areas of North America. These subverted the normal ecology of the Earths, causing devastating effects to the environment as their alien nature was incompatible with the worlds they were introduced to. Initially, they plant men and their vile vegetation seemed to overwhelm their superhuman opponents.

Ker Sed and his papa Bur Sed wielded staffs, which were the source of their amazing powers. This included the power of flight, teleportation, force fields and the ability to redirect any force projected against the ones who wield them, which made the Seds nearly invincible when facing individual Leaguers and the combined team. Similarly, the various forms of plant life which they introduced on Earth-One proved difficult to remove.

Lord Cob and his master King Tassel had a vast army of creatures like themselves. While mentally controlling their fellow Plant People, the Rykornian’s forests quickly grew to gigantic size, sucking the nutrients from soil of which it was planted. 

Eventually, the Justice League hatched a scheme where they tricked the father-son foes by pretending to aid them I  spreading their seeds, distracting them as their staffs were stolen from them. Now susceptible to the excess oxygen in Earth-One’s atmosphere, Bur Sed and Ker Sed had to flee from that planet once their staffs were given back to them.

Similarly, Wonder Woman and the Holliday Girls constructed and unleashed a gigantic mechanical vacuum, capable of capturing King Tassel, Lord Cob along with their Plant People and large stalks. With this device, the Amazing Amazon exiled them back to Rykornia, which she was able to thrust back into space.