The Flesh Feaster is a handicapping enemy, not posing much direct of a threat to your life but an encounter with one gone awry will put you at a lasting disadvantage.
The Feaster eats flesh, as one could infer from it's title. It prefers to eat off the limbs of victims and leave them helpless. This is certainly bad news for anyone who likes having limbs.
Being in close combat with the Feaster will give it ample opportunity to eat off your limbs, and surviving without them is not ideal.
Should it eat one of your arms, you will be unable to use one of your weapons, greying out one of your three weapon slots. The weapon in this slot can be dropped, but not fired or swung. The weapon you were wielding when your arms were removed will be the one greyed out. The weaker variants can target your arms up to two times, leaving you with only one weapon slot. The strongest variant can completely remove your arms and leave you defenseless.
Should it eat one of your legs, you will receive a speed downgrade except when jumping. To keep your speed up, you will need to constantly hop around, which generates more noise. The weakest variant can eat your legs only once, but the stronger ones can eat your legs two times, and make you completely immobile unless you're hopping.
Getting Limbs Back
Limbs can be regrown, given time and proper medical procedure. Any health-restoring pickups, items, etc. used at full health will contribute to your limb points. Reaching a threshold of limb points will restore a limb of your choice and reset the counter back to 0, allowing you to fill it again if you are still missing some limbs, or removing the counter if you have no more missing limbs.
There are many types of Flesh Feasters, I'd wager the number's somewhere between 2 and 4.
The standard. The classic. Just your average, everyday Flesh Feaster. Can eat off your arms twice and your legs once. The single leg loss penalty is a loss of 33% speed.
Meaner, meatier and munchier. Can eat off both of your legs and gives a harsher penalty for losing a single one. The single leg loss penaly is a loss of 50% speed, and 80% for double leg loss. Any limbs lost to the Meat Muncher will require more limb points to be recovered.
The ultimate in lean, mean, flesh-eating machines. Can eat off both of your legs and eat all of your weapon slots. Requires the same amount of limb points as the previous iteration. Receives a damage boost for each limb that it eats.