No, 3 million electric toothbrushes were not used in a DDoS attack::A widely reported story that 3 million electric toothbrushes were hacked with malware to conduct distributed denial of service (DDoS) attacks is likely a hypothetical scenario instead of an actual attack.
Next? Hell, that kind of thing is old news already.
https://arstechnica.com/tech-policy/2016/12/maker-of-internet-of-things-connected-vibrator-will-settle-privacy-suit/