This study investigates the impacts of using the quillbot application on students essay writing. Employing a qualitative case study approach, data were collected through semi-structured interviews with seven participants. The analysis revealed five major categories of difficulty: (1) limited understanding of the writing process, particularly in planning and structuring ideas before using Quillbot; (2) varied motivation and attitudes toward writing, which influenced how strategically the tool was used; (3) high dependence on the application, especially for grammar and coherence, sometimes leading to shortcut behaviors; (4) perceived impact on writing quality, including both improvements in clarity and concerns over loss of voice and meaning; and (5) awareness of academic integrity, where students were cautious about plagiarism but sometimes lacked clear boundaries in using AI-generated outputs. Despite these challenges, the study found that some students employed reflective and strategic approaches, such as revising Quillbot suggestions critically, using the tool selectively, and maintaining their own writing voice. The findings emphasize the need for instructional interventions that focus on writing development, digital literacy, and ethical tool use. Future research is encouraged to explore comparative use of other AI-based tools, include a larger participant base, or examine teacher perspectives on the role of paraphrasing tools in academic settings.