When a human being is infected with the T-Virus, metabolic activation takes place leading to a constant state of hunger. Eventually, the food source of the resulting zombie will run out and it will eventually die from starvation. However, a unique reaction in some zombies leads to the complete reformation of the host's cells, leading to a mutation. This mutation leads to one becoming a "Licker".
The Licker loses its eyesight due to the expansion of the brain, leading to the loss of much of the skull and particularly the upper section of the face leading to the complete degeneration of the eye cavities. In exchange, they develop an acute sense of hearing to accommodate this loss. The skin rots and peels away completely, leaving the Licker's deformed muscle tissue completely visible, where it is reformed. This enhanced muscle structure gives them greater abilities in comparison to average zombies, allowing them to jump great heights and distances and move more quickly with heightened agility and movement.
Resident Evil 2
Resident Evil 2 brought about the introduction of Lickers, and they somewhat functioned as a replacement for the Hunters in the original Resident Evil. However Lickers are introduced much sooner within the game.
Like Hunters, Lickers are extremely agile and fast, have an attack that can commit an instant-kill against the player, and can withstand more damage than the typical zombie. Lickers also have the added advantage of being able to climb up and rest upon flat surfaces, including ceilings. However they often tend to make a breathy growl of sorts, that along with the squishy noise of their movements makes them easy to pick up should one be close by.
A licker usually takes between 2-3 shotgun or crossbow attacks to kill one. Though because of their lack of sight, players can potentially avoid encounters with one should they walk past rather than run. However if a player gets close enough, a Licker will always catch on to their presence and give chase regardless of their movement speed. While they can sometimes be encountered alone, they will more often than not be found in groups of at least two.
Their attacks often involve their claws; they will swipe the player's leg when close, and when encountered at a distance will give off a loud shriek and then leap through the air in an attempt to maul the player. They will alternatively strike with their tongue and attempt to strangle the player; if the player's health is in the Caution state, there's a high chance the Licker will rip off the player's head completely.
There is a tougher variant of the Licker that'll be encountered later in the game. They are of a noticeably different shade of color from the regular red Lickers, with a more murky grey/green color to them. They utilize the same attacks as a regular Licker, however they will deal more damage; this variety of Licker can also withstand more damage at that, often taking at least one more shotgun/crossbow shot to kill.
This form of Licker is also amongst the B.O.W. roster in Resident Evil: Survivor. Though because of the game's nature as a light-gun shooter, they are encountered in much bigger groups and are more susceptible to bullets.
Resident Evil 5
Officially coined 'Licker β', this variety of Licker is an advanced that has been injected with the progenitor virus. While they largely look the same, they are noticeably bigger in mass with more muscle. The most notary difference is for their increased resistance to damage, allowing them to withstand copious amounts of firearm fire. Unlike the original Lickers, however, Licker β's have one particular weakness: their exposed heart. Because of this, should the player manage to knock a Licker onto its back, they can then commit an instant kill by way of a button prompt allowing them to stab the Licker directly in its heart.
These too lack the ability to see, though once more have highly acute hearing. As such it is highly possible during some occasions for the player to avoid combat with Lickers altogether so long as they walk past without firing their weapons. Unlike in Resident Evil 2, Lickers will not respond no matter how close by a player may be, so long as they continue to walk.
Licker βs still attack using the same array of moves, including their tongue which they now use to pierce a character's shoulder continually draining the character's health the longer it stays. Their large claws are also an asset Licker's will often use given the chance if a player is close enough; if not they will leap across the air -- potentially grabbing the player and killing them instantly by stabbing them if the player's partner can't save them in time. Like the original Licker enemies, Licker β's have the ability to maneuver across flat surfaces, such as crawling up walls and across ceilings.
Lickers are encountered throughout the Hellfire scenario, and function much as they do in Resident Evil 2. However the end boss of the level is what is called a 'Regis Licker', which is the stage between a zombie mutating into a full Licker. It mostly retains its humanoid shape, although it has adopted a blood-red skin pigment, has grown the trademark tongue, and will make the same breathy growl noise they are known for.
It is fought whilst it's stuck in a ceiling vent; it cannot move, but its tongue gives it a great range of attack. It will primarily use it as a whip, but will also at times unleash an incredibly fast flurry of swipes. If the player gets too close, it will then pick the player up and attempt to strangle him/her with its tongue.
- The Licker was named by R.P.D. officers on September 27, 1998, after the sudden appearance of the "Licker" and its quick decimation of a number of officers.
- In Marvel vs Capcom 3 and its Ultimate rerelease, Lickers appear in the background of an Umbrella laboratory stage alongside the T-002.