The cactus was in the window to try to give it some light, but over time the sun appears to have perished its (plastic) plant pot. When she picked the pot up to examine the cactus, the pot disintegrated, whereupon the cactus made a break for it and attacked her.
The vicious assailant was swiftly recaptured and after a brief period in custody was sentenced to incarceration in our green waste recycling bin.