Brown, Rainbow and Unstable Ants are fairly harmless. Red ants are not! Neither are Termites (which can easily be confused with ants). There is rumored to be a Red Ant colony in The End, providing a convenient way back!
Be sure to collect plenty of nests and keep them in a zoo cage near your home so you can teleport anytime!
Right-click an ant to teleport to a new dimension!
Brown Ant takes you to the Utopia Dimension. There are no mobs and it is very peaceful.
Red Ant takes you to the Mining Dimension. There is a ton of material but it's not always safe.
Rainbow Ant takes you to the Village Dimension. So many villages to save!
Unstable Ant takes you to the Danger Dimension. Be careful. No, seriously.
Your Girlfriend and other pets will automatically teleport to the ant worlds with you. Unless you've told them to sit, of course.
How to Kill
A good pounding with your fist usually works fine.
Found: Almost everywhere