## Core Concept
Haloperidol is a typical antipsychotic medication primarily used in the treatment of schizophrenia and other psychoses. It works by blocking dopamine receptors in the brain, which can help reduce psychotic symptoms. However, this blockade can also lead to various side effects, particularly at high doses.

## Why the Correct Answer is Right
Haloperidol toxicity is known to cause extrapyramidal symptoms (EPS) due to its potent dopamine D2 receptor antagonism. EPS include a range of movement disorders such as dystonia, parkinsonism, akathisia, and tardive dyskinesia. Among these, **tardive dyskinesia** is a particularly concerning side effect associated with long-term use of typical antipsychotics like haloperidol. It is characterized by repetitive, involuntary, purposeless movements that can be irreversible.

## Why Each Wrong Option is Incorrect
- **Option A:** While certain antipsychotics can cause QT prolongation, this is not the most directly associated toxicity with haloperidol compared to its extrapyramidal effects.
- **Option B:** This option is not specified, but if it relates to another side effect, it's less directly associated with haloperidol toxicity compared to EPS.
- **Option C:** Similarly, this option is unspecified but would be incorrect if it doesn't relate to EPS or is less directly related compared to the correct answer.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that **tardive dyskinesia** is a risk with long-term use of typical antipsychotics like haloperidol. Monitoring for early signs of EPS and adjusting treatment as necessary can help mitigate this risk. The Abnormal Involuntary Movement Scale (AIMS) is a tool used to assess and monitor tardive dyskinesia.

## Correct Answer: D. Tardive dyskinesia.