Lovelings is a species I created because funny what ifs, Lovelings are capable of merging into other species that are capable of producing love like a regular changeling. However, unlike it's counterpart, they put themselves in a relationship with their victim and over time they drain their love until the pony either rejects them or is too weak to continue the relationship, thus causing the Loveling to break up with it's target and find a new one. Lovelings are pretty much Toxic Relationships rather than Toxic Friendships.
The Loveling in the drawing is named Aortic (Lovelings are named after a part of the Heart) or uses her pony form name, Love Bug, to roam around Ponyville.