|Mark of Transference||+|
In the episode Crusade Lana received the mark when she visited Isobel's tomb in Paris, and it is possible she was temporarily possessed then as Lana woke up in her bedroom immediately afterward. When she purchased the spell book, the mark on her skin combined with the identical mark in the book, which was stained with Isobel's blood. This allowed Isobel's spirit to possess Lana. Once Lana killed Genevieve Teague, the tattoo vanished, the spell was broken and Lana was freed from being controlled by the Countess ever again. The Mark of Transference on Lana's back is also the symbol on the Crystal of Water, the Kryptonian symbol for water/transference.