Invisible Vampyre
A race of “Invisible Vampyres” were native to the planet Sanguivor. They ordinarily killed their victims, but, if interrupted mid-bites, the victim could become a vampire themselves.
As the transformation occurred, they would gradually become invisible, although once the transformation was complete the vampire could seemingly be visible or invisible at will, as demonstrated by Acantha. The metamorphosis could only be halted by a prick from the fang of someone who had themselves already been partially transformed into a vampire, then cured.
Briar was bitten by an Invisible Vampyre during her first adventure with Century Smith, putting her on the path to transforming into the malevolent vampire Acantha. However, interference by an unwitting Jenny Nowhere resulted in Briar's timeline being split in two unstable futures, one where she became Acantha, and one where she was cured using Acanth's own fang from the future where she ceased to exist. Acantha tried to stabilise her existence and push the human Briar out of reality, but instead ended up merging with Briar, who retained some of Acantha's vampiric ability but reverted to her original personality and name. (PROSE: Century Smith and the Time Terror)