After an Otherworld transition at the Green Lion Antiques Store, Harry Mason looks for a way to make it to the Resort Area and deviates through the Silent Hill Town Center. When Harry reaches the second floor, he encounters two smaller Twinfeelers feeding on a corpse. However, when Harry attempts to walk towards it the catwalk gives away and Harry falls into the previously unreachable gun shop, which a larger Twinfeeler inhabits.
The Twinfeeler is an oversized moth larva, with purple-colored blood.
The Twinfeeler is capable of spewing harmful red liquid. This monster can also attack by burrowing itself in the sand and bursting out in an attempt to strike Harry; although, it is possible for the Twinfeeler to damage Harry by simply barging into him.
After the Twinfeeler has taken enough damage, it apparently curls up and dies, an animalistic survival trait that appears in multiple species of fauna. Shortly after however, the Twinfeeler springs back to life and escapes the arena by crashing through a wall, inadvertently making up Harry's own escape. Later on, after visiting Alchemilla Hospital, Harry encounters the Twinfeeler in its full adult form, the Floatstinger, a moth-like creature he battles and defeats atop a water tower in front of Alchemilla. Its death brings back a shift to the Fog World.
Alessa Gillespie had a number of insect specimens in her room, these including butterflies and moths. The Twinfeeler's presence is unlikely to be a result of a fear of insects, but possibly a fear of her insect collection returning to life as a form of "retribution" to the fate they've ended with. The Twinfeeler, much like the Creeper and the Floatstinger, is merely a giant version of the insect itself, with no major difference in appearance; this would suggest that Alessa did not directly fear the bug for what it was.
Also notable is that the Twinfeeler could symbolize (arrested) development, as it is essentially just a colossal moth larva. The Twinfeeler could be an instrument to get a player to consider Alessa's fate: her womb was the incubator for the Order's developing God, but when she split her soul in two, those of the Order tending to her acknowledged that any power they could draw from her would be highly insignificant in comparison to what could've been achieved if her soul was fully intact. An analogy can then been made with the evolutionary stages of a moth: The Twinfeeler is "stuck" in its larval stage, resulting in it being so oversized, just as the unborn god within Alessa was stalled by the breaching of its foster mother's soul. The Twinfeeler evolving into the Floatstinger could be considered symbolic of Cheryl Mason rejoining Alessa's soul.
- The player can find the Rifle in the same room that the boss fight takes place in. It is a good way to kill the boss, but there is a scarcity of ammo available to the player at the time.
- The player can ready a firearm and kill the smaller Twinfeelers, causing the radio to stop emitting static.