The song 'WILDFLOWER' by Billie Eilish delves into the complexities of a relationship haunted by the lingering presence of a past lover. The lyrics explore feelings of insecurity, comparison, and the struggle to move on, symbolized by the metaphor of seeing the ex-partner in the back of one's mind like a fever, burning alive. The song captures the internal conflict of trying to let go of the past while being haunted by memories, questioning the depth of the current relationship and the impact of past experiences on the present.