Question: In my story, I want a creature to be immune to bullets, but giving it bulletproof skin seems too obvious. I want it so that you could shoot the creature a few times at its seemingly vital spots (the head, heart, etc.), but it won't die right away and can still escape or attack you. The best way to make sure it dies quickly is by draining most of its blood, which means you have to get close enough to cause a large wound with a bladed weapon.

Yes, I know you can just use a really big gun or explosives to achieve the same effect, but in this scenario, the options are limited to something relatively cheap, lightweight, and doesn't cause a lot of collateral damage. To give you some image, the creature is about as agile, as strong, and as big as a polar bear.

Preferably the reason it's immune to bullets is based on real animals, or at least something that could exist in the natural world.

Answer: 
Um why not use an actual polar bear? Or something very similar; bears, especially the big bears, (Polar and Grisly) are notoriously hard to kill with small calibre rounds, the combination of muscle layers, fat, and fur over their primary body cavity makes getting at their organs really unlikely with handgun rounds. They also have very thick muscles and bones in their skulls so headshots often lodge near the surface breaking bone but not punching through.
How big is this creature allowed to be?

I'd like to take this in a different direction than the other answers: **make the creature "sparse"** (as the crown of a tree) and/or large (as a coral reef), so that point-effect weapons (such as bullets) have a very low chance of doing significant damage.

Maybe combined with vital organs somehow being distributed or in unforeseeable places, and you really have to hack it to pieces in order to kill it.

I realize this makes it look more like a *very lively plant* than an animal, but depending on your reality ... that line can be surprisingly blurry anyway.