**Core Concept**
The question tests knowledge of substance abuse and its clinical manifestations, particularly focusing on the identification of a specific agent based on unique physical and psychological symptoms.

**Why the Correct Answer is Right**
Given the symptoms of visual and tactile hallucinations along with black staining of the tongue and teeth, the description points towards the use of cocaine, especially crack cocaine. Cocaine use can lead to hallucinations, and the black staining is indicative of poor oral health often seen in crack cocaine users due to smoking the substance.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option provided, it's challenging to give a precise reason, but generally, other substances like heroin or methamphetamine do not typically cause black staining of the tongue and teeth as a hallmark sign.
**Option B:** Similarly, without the option, it's hard to comment, but substances like LSD or PCP can cause hallucinations but are not typically associated with the specific oral health issues described.
**Option C:** Again, lacking the specific option, but it's worth noting that alcohol or benzodiazepine withdrawal can cause hallucinations but not the specific dental staining mentioned.
**Option D:** Assuming this is not cocaine, then it would be incorrect because the specific combination of symptoms points towards cocaine use.

**Clinical Pearl / High-Yield Fact**
Cocaine use, especially smoking crack cocaine, is notorious for causing severe dental problems, including tooth decay and gum disease, partly due to the vasoconstrictive effects of cocaine which reduce blood flow to the gums, and partly due to neglect of oral hygiene.

**Correct Answer:** D. Cocaine.