Starfield:Heatleech

Heatleeches are small, passive creatures which are considered pests to much of the Settled Systems. They feed primarily on heat, and are common sights on board ships and abandoned settlements. They pose no threat to the player, and run away when threatened.

During the events of the quest Hostile Intelligence, it is discovered that Heatleeches are the juvenile form of of another creature which the editor has removed because wow what a spoiler to just put without any kind of warning.