Our list of nominees for a thumbs down is long this week. It includes the Airbnb homeowner in Big Bear who has been fined $5,000 fine and ordered to apologize for canceling a guest’s reservation moments before she arrived — because the guest is Asian. It also includes the woman who bought Rice Krispies treats, a brownie and a slice of cake at a Rancho Cotate High School bake sale last week and paid with a fake $100 bill. (She made off with $80 in change and didn’t even have the decency to leave the brownies. A suspect was arrested Sunday). But our biggest downward digit goes to those responsible for a series of attacks and robberies on individuals in London on Thursday. Their weapon of choice? Acid.

The culprits rode about London on mopeds for about 90 minutes and tossed acid in the faces of their victims at stop lights. In some cases, the attacks occurred during a robbery attempt. Two teenage boys, one 15 and one 16, have been arrested and face multiple counts of assault with intent to cause grievous bodily harm, robbery, attempted robbery and possession of a weapon. Police say acid has become a gruesome weapon of choice, particularly for gang members in London. The trend has prompted the circulation of a national petition calling for tougher laws on the use of acid and similar products. So far it has received nearly 400,000 signatures. What in the world prompts people to do things like this? Thumbs down on whatever it is.