Could be a fungus like Vladimir said, could also be an insect egg or just dirt on a bit of fluff. However, I'm more concerned with how dusty the leaves are. I may just be dust or it could be the beginnings of a spider mite infestation. It's a good idea to wash off the leaves from time to time, like maybe every 4-6 weeks. Take them outside and hose them off, or if that's not possible, put them in the shower and shower them off with cool water. Then let them drain well and put them back where they were. It helps prevent spider mites as they're attracted to dusty plants. And your plants love the rinsing off!

Wonder, Garden, and Norma..Thanks for your replies..lol You guys had me LOL'ing away..If the pillar was going to turn into a moth, it'd had been out on it's slinky butt that night, but it's going to be a non-native butterfly, so I feel bad tossing it outside in freezing temps. It's been 40's during the day, 20's at night. I am very upset about my, once beautiful, Crown of Thorns, and you guys are right, if it had/s babies or friends, that'd be the end of my plants. I'm not sure that particular Crown will make it..One of my fav succulents. Does anyone know if caterpillars are egg layers? It's living in the sink, surrounded by leaves and grass. Plus I've been misting leaves for moisture. My dh, (nut) suggested placing it in the gh..If I had a gun...lol..j/k.. We can't find information, especially about someone who lives in the midwest, keeping a caterpillar, indoors..lol. I found a site that displayed 600+ caterpillar pics, but none fit the bill. I discovered, the standard caterpillar is 1-2" long..this guy is nearing 4"..A 4" pillar is called a King. Some pillars have stingers, unlike a bee, wasp, etc..I can't recall which part of their body contains venom for protection..when someone or something brushes/touches them, the venom is absorbed through pores..it can cause mild irritation to extreme, some ppl have to seek medical attention..3 ppl picked/touched him/her, without harm, excluding myself..I lifted him w/a stick..lol. To top that off, yesterday, my dogs were in the yard. The smaller dog was licking something..I thought he took one of his stuffed animals outside..I approached, found he was licking a baby possum..the rodent was about 8", no mom or dad nearby..I hurriedly lifted my dog, brought in the house, and washed his mouth..Though we're not possum lovers, we felt sorry for this little guy..Later in the night, he was standing before the glass doors looking inside..it was strange!!! He/she wanted in..out of the cold, and dinner..of course we didn't adopt him, too..I hope he finds his mother. What next??? An elephant? lol Norma, I know how you feel about spiders, and respect your 'courage,' lol, but I'm arachnophobic..as for mealy, it's a matter of working with plants, cleaning areas and plants, inspection, etc.. Even seeing the tiniest spider, I'm a slam-dunking, Michael Jordon..lolol, running for dear life, w/o the pay. But seriously, does anyone have any idea where or how to keep the pillar? I don't want him eating my plants, but will spare leaves. Mainly foliage from large Pothos and cleaned outdoor grass. I cannot believe he ate leaves from a Euphorbia, a toxic plant, yet alive and well.. So far. Thanks for everyone's help..Toni

Photo is a tad fuzzy. But perhaps it's a nymph of the solanaceous planthopper. If so, it's often a late season pest and/or pest of stressed plants. If you have only several, squish 'em.

well... didn't touch it on purpose. i thought i had a fuzzball or something on my shirt so i went to pick it off and when i did so i realized it was alive lol. i'll go check out the Puss moth Catepillar and see if that's what it is. thanks :)