As we know, space is gendered and far too often gendered to exist solely in the binary. But, just as sexuality is now understood to reside on a spectrum, gender is beginning to be afforded the same treatment in academia, politics, and even sports. Consequently, spaces traditionally understood in terms of gender absolutes are becoming sites of conflict and liminality. Even in the most progressive of feminist communities, cis-women and men are encountering unexpected difficulties accommodating those outside the gender binary. This research explores these struggles through the member-leagues of the Women’s Flat Track Derby Association (WFTDA). This global organization, charged with the governing and promotion of the sport of women’s roller derby, has come under attack in recent years from members of the transgender community who allege that routine acts of transphobia and trans-exclusionary radical feminist rhetoric have been directed at trans skaters by its cisgender members in the WFTDA in the wake of their 2015 Gender Statement. This statement and policy change opened the once cis-centric, women-only spaces of the organization to transgender and gender expansive athletes. In this research, I chronicle my experiences navigating the first year of my medical transition from male-to-female as a member of one of these groups – the Los Angeles roller derby community – and the unplanned activism I undertook as part of my struggle for inclusion and acceptance in this subculture as a transgender woman. Here, I utilize affect theory and the concept of fear to understand the systemic transphobia manifesting within this once cis female exclusive sport. Additionally, I analyze this unexpected gender bias through the lens of ‘edgework’, the sociological study of high-risk behavior. Finally, I draw on the primary data I collected from interviews with twenty-two trans and cisgender skaters in the Women’s Flat Track Derby Association, my own autoethnographic account, and the field notes from my participatory action research with the TIGER Derby Collective to theorize that much of the anti-trans sentiment amongst cisgender skaters in the organization is due to a fear amongst cisgender skaters that women’s roller derby is under attack by a gender-diverse minority group who challenge the once, cis-defined, women’s-only spaces of the WFTDA.