The pordenfer is a nether mob, and, as of yet, the only nether mob to appear on peaceful. They wander around like pigs. And they're useful like pigs too. When killed (they have 7.5 hearts of health), they drop pordenfer meat, which you can then cook in a furnace to get cooked pordenfer meat.
When uncooked, pordenfer meat gives you food poisoning (hunger) for thirty seconds. Why would you ever want that? Because it also gives you fire resistance for thirty seconds.
"But doesn't this make fighting blaze too easy?"
I say no. Most people I know just snipe the blaze from afar, with no danger whatsoever. If you run up close, blaze still have a melee attack, and you'd need to defeat them in less than thirty seconds or you'd waste time eating another uncooked piece of meat. And that hunger poisoning, for thirty seconds, is enough to starve you, thus hampering you further. The uncooked meat is not intended for combat. It is intended for short stretches of lava, or protection in the areas of the nether more densely filled with fire. Much like the golden apple. It's inefficient in combat, and is mostly just useful for recovery. This is inefficient in combat, and mostly just useful for exploration in the nether.
When cooked, pordenfer meat gives you half a hunger bar. Why would anyone want that? Because it also gives you 16 saturation, making it the most saturated food item in the game.
Pordenfers spawn on soul sand, but are not hampered by its effects. Or rather, they are, but do you see those long legs? When not on soul sand, they move slightly faster than the player's walking speed. They can also jump up to four blocks high, and are somewhat resistant to fall damage (as if they were wearing boots with feather falling II on them). So, when threatened, what do they do? They turn toward the player and jump over their head, and proceed to run away. So, while they pose no active threat to the player, they certainly can be a hassle to kill.
Pordenfers can be bred with netherwart every fifteen minutes (three times as long a wait as farm animals). I need say no more. Should nether villages ever be implemented, they may come with pordenfer farms. Attacking those pordenfers provoke the villagers to attack (or activate whatever defense mechanisms they have).