Systemic disruptions from COVID-19 have transformed the assessment landscape in Canada and across the world. Alongside repeated shifts to emergency remote teaching, large-scale assessments and summative evaluations were cancelled in many jurisdictions, and repeated concerns were raised about ensuring equity and access to quality education. This paper investigates the rapid -- and in many cases innovative -- responses teachers offered to these challenges at the height of the pandemic. Drawing on prolonged semi-structured interviews with 17 secondary school teachers in Ontario, Canada, the paper provides a detailed account of Ontario's approach to assessment during COVID-19, exemplified by participants' lived experiences. Results highlight the notion of emergency remote assessment, the vital role of assessment in stemming widening equity and well-being gaps, and emerging consequences from this period. These data offer critical insights into the future of our forever-changed education landscape, and position classroom assessment as a priority player in this work.