I got a sample bag from the supermarket when I did the groceries last week. It contained a packet of long-life chocolate pudding. R and I sampled it and, boy, was it awful! Even R did not want to eat it - and he eats almost anything!!
So rather than waste it, I put it on the table for some finger painting. It started out quite thick, but the more R played with it, the more it turned into a milky substance.
He did have fun playing with it, spending about 20 minutes spreading it around his little table. He wasn't too sure about the sticky consistency at first, but soon got over it.
Clean-up took a little while, but it was worth it for the enjoyment R had.