**Core Concept**
Delirium tremens (DTs) is a severe form of alcohol withdrawal characterized by sudden and severe changes in mental status, including hallucinations, agitation, and autonomic instability. The hallucinations in DTs are typically tactile or visual, but can also involve sensations of insects crawling on the skin.

**Why the Correct Answer is Right**
The sensation of insects running over the skin, also known as formication, is a common symptom of DTs. This is thought to be due to the release of stress hormones such as cortisol and adrenaline, which can cause an increase in the activity of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is involved in the regulation of the body's response to stress, and its activation can lead to a range of symptoms including hallucinations and formication.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specifically describe the sensation of insects crawling on the skin. While it may be a feature of DTs, it is not the most accurate description.
**Option B:** This option is incorrect because it is a feature of withdrawal from other substances, such as opioids or benzodiazepines, rather than alcohol.

**Clinical Pearl / High-Yield Fact**
DTs typically occur within 48-72 hours of the last drink in a patient with a history of heavy alcohol use. The symptoms can be severe and even life-threatening, and prompt treatment with benzodiazepines and supportive care is essential.

**Correct Answer: C. Formication.**