R.O.S.A. was a nursery android utilized for the Springfield Nuclear Power Plant's daycare center. As such, she oversaw the toddlers placed within the daycare, including assigning them various tasks that, if they succeed and get acknowledged via a tap, they get free donuts. On one particular day, after a four-hour task everyone save for Gerald Samson (who was placed in time-out for presumably poor behavior) completed, everyone managed to get a donut. When Gerald tried to get the remaining donut, R.O.S.A. sealed the donut container and said that she cannot allow him to get a donut. Gerald, angry, then proceeded to remove the "Energize It" batteries in her back, shutting down her primary functions, although her AI retained some functionality, as evidenced by her asking what Gerald was doing. However, as she asked him, Gerald proceeded to steal some fuel rods and forcibly placed them in the battery inserts in her back, which ended up causing her to become unstable, including developing green cracks and undergoing a meltdown, with the toddlers except for Gerald becoming horrified. Maggie Simpson, witnessing this, acted fast and guided R.O.S.A. to the miniature reactor core in an attempt to prevent her from causing a meltdown. However, it ultimately was for naught as it ultimately caused the plant to melt down regardless while Maggie ended up becoming Sky Finger.