Danaus plexippus

Perfectly safe to be near, but poisonous to eat, which is the whole trick it uses to survive.
The caterpillar eats milkweed and stores the poison in its own body, so birds learn to leave it completely alone.
This one is poisonous, which means it hurts you if you touch it or eat it. It cannot chase you, so the rule is simple: look, do not touch.
Always ask a grown-up before you touch any animal or plant. If something bites or stings you, tell an adult right away.
Source: our source list
Read more about the monarch butterfly at Wikipedia.