A new event to introduce new zeds, bosses, maps, and weapons, the event would include cosmetics and maybe even a playable character that fit the theme only attainable during the event. The bosses, enemies, and weapons would be permanent. This is just a general draft, most parts do not have specific examples or details.
The entire event is as the name suggests based around the introduction of elements from the works and ideas of the universe(s) created by H.P. Lovecraft, so more cosmic horror than mutated lab experiment than the current game theme.
Weapons- Living weapons that would be medium tier to buy, but have the capacity to evolve during the match when specific requirements are met raising them to high tier weapon damage and performance.
Enemies- Introduction of two to three enemies that fit the idea of lovecraftian monstrosities, maybe one or two could in inflict a melee range activated short lived debuff that inflicts insanity making it hard to tell friend from foe and enabling friendly fire for the duration.
Bosses- The spawn of Cthulu would essentially be a scaled down version of the elder god to pay homage to the great dreamer himself.
Maps- No clue really, but maybe easter eggs of Cthulu, Yog-Sathoth, or Shubniggurath in the background of the map just for aesthetics