"Fuck it." Karen said. She'd love to slowly devolve all the women in the world, but she wanted to be the only one left so men would come to here.
"All women in the world, become animals!"
The ring then got super hot as it was a lot to ask for and Karen screamed as it burned. In fact it got so hot it melted her finger right off her hand. She screamed bloody murder as she ran to get a towel to put pressure on from the blood she was losing. As she reached the bathroom she tripped a hit her head on the toilet, knocking her unconscious. That's when changes started to happen. Stupid Karen had forgot to exempt herself from the wish as her body changed. Her body shrank quickly, as a long rat tail sprouted above her feminine backside, which was looking more animalistic by the minute. Her breasts shrunk down as little rows of teats popped up on her abdomen. Her head shrank down and her face was now ratlike. Soon, all that was left of Karen was a pile of clothes and a dead rat, as the blood loss from her little finger had been so much that by the time her body had shrunk down to the size of a rodent, she had loss so much blood, that her little body shut down.
Karen was now dead, and so was womankind.