We found some of these in the bottom of a potted plant we brought home from the nursery this week.
Although it has antennae, it definitely has too many legs to be an insect larva.
In fact, you can see that it has two pairs of legs per body segment. That means it is a millipede.
Millipedes are often found in damp soil or rotting logs. Most feed on decomposing plant matter, so they are nature's recyclers.
Millipedes do not bite or sting, and are relatively harmless. They do have the ability to emit various chemicals to defend themselves (depending on the kind), so it is best not to pick them up. Their main defense, however, is to roll up into a ball.
If you are interested in finding out more, Enchanted Learning has an information sheet with a nice drawing showing all the parts of a millipede.