Walking through a dimly lit garden at dusk, a man briefly perceives a coat hanging on a hook as a person standing still — but on looking more closely, he immediately recognises it correctly as a coat. What is this?

This is an illusion: a misperception of a real external stimulus (the coat), perceived momentarily as something categorically different (a person), resolving quickly once attention is directed toward it — exactly the pattern the phenomenon's own recognition features describe, including the classic triggering conditions of poor lighting and brief glance. It is not a hallucination, since a real stimulus (the coat) was genuinely present and accounts for the misperception. It is not a pseudohallucination, since there was a real external object involved, not an inner, self-recognised-as-unreal experience. And it is not a delusional misinterpretation, since the perception itself was briefly inaccurate and then self-corrected, rather than an accurate perception having a false belief attached to it.