Nutella is basically oil, ground nuts, cocoa powder and sugar.
You can make something of a similar texture using shortening/margarine, cocoa powder, golden syrup blended together Ratio: 3parts margarine/lard 1part syrup Cocoa powder - add until you get the right colour (powder paint if you don't mind the taste - this will make the colour more opaque) Add some ground nuts or bran flour for texture (nuts are more expensive), a few beaten eggs if you wish. Thin with vegetable oil.
Not the easiest thing to wash off as there's virtually no water in it but, in a way, that's the beauty of it!
You can make marshmallow fluff (there are lots of recipes) as long as you live in a region where high fructose corn syrup is readily available. I don't (UK) so I haven't tried this one.
On my profile page is a video where you can make inexpensive slimy goo. With brown poster paint, it looks like mud or chocolate. All you need is arrowroot flour and a stove.
X-Lube It is powdered polyethylene oxide. Safe, non toxic. It is like the ghost busters slime. I mixed in my favorite St. Ives Lotion, Smoothing Rose. Made a nice slippery slime.
I just used it in the bathroom. Makes a sticky mess.
FYI follow the mixing instructions you'll be fine. On Amazon people recommend hot tap water. Like 50 to 60 Celsius. Mix hard with a fork up to a minimum. Let it sit, mix again in 20 minutes. Let it develop an hour. Good to go. My first time I mixed two litters extra thick. If mixing much. Place the measured amount in a separate small container As soon as that hits the hot water, go! to break it up or it will clump. No mechanical mixers or it will break the polymer chains. Second time I just mixed 500mL and then added a couple of bottles of lotion and it is was great. One one bottle of the X-Lube will make 20+ litters. It is a lube so it does feel great. I played with a p spot tool as well. Amazing results. Remember this is a water based substance so only mix with water based things. You can add probably powdered paint or other things to tint. I like the sexy smell of the lotion.
On a side note check out the carnivore diet. So easy to cook and eat. Arguably the most healthy diet actually. Search a video called. Plants are trying to kill you. Carnivore supports our hormonal health. They say you feel like 20 again. What they mean is you will feels as horny as a teenager again. Oh ya.