This sounds like some kind of DDOS attack like the ones that involved connected light bulbs. Malware gets into the light bulb or washing machine and repurposes the infected device to flood targeted servers:

https://www.sciencealert.com/here-s-what-we-know-about-the-massive-cyber-attack-that-took-down-the-internet-on-friday

Obligatory meme wisdom:

https://biggaybunny.tumblr.com/post/166787080920/tech-enthusiasts-everything-in-my-house-is-wired

Why would you connect your washing machine to WiFi in the first place? Like legitimate question.