Animals!

We exist in a fragile eco-system, ultimately our entire bio-sphere is symbiotic. That said, if threatened by Bears etc, it is ethically acceptable to defend oneself with Explosives.

Bear
Growly. Avoid-worthy. Flammable. Swimmy. Trappable.
They move at a steady pace in your direction, but are easy to outrun.
Notoriously claustrophobic, they don't like being confined.

Wolf
Moves when you do. Once they are on your trail, they are difficult to shake.
Climbing out of danger often helps. As do traps, lasers, mines etc.

Bull
Chargy. Pointy. Turns to Right if it has to. Flam-a-bull. Pushes blocks. Non-swimmer.
Isn't really bothered by your existence, just likes to run around like an idiot.

Spider
Jumps like a Chess Knight. Blind, reacts to sound. Fooled by slippers not invisibility.
Don't just run away, or you will get eaten. Instead look where it can jump next, and avoid that.
If you stay on the walls, and run around near voids, lasers or traps, they will fall for it every time.

Hatchling
Moves diagonally one square. Blind, reacts to sound. Fooled by slippers not invisibility.
These are different to spiders, and not just a lazy re-use of artwork.

Cat
Stupid animal. Why is it running away? You're here to save them!
A bit of cat food will attract them.
Immune to lasers, traps, or other animals.
But they don't like being set on fire, or pushed down holes. (Which is understandable).
Sometimes they snooze, which makes them easier to catch.
If you get wet, any collected cats escape.