Analysis of spontaneous speech error?

[I am a native speaker of American English.]

It's been a few years since I got my BA in Linguistics, and about as long since I've used any of what I learned. Thus, there's quite a bit I've forgotten.

The other day, I intended to say, "The shape looked odd." What I actually said, however, was, "The shaped look odd."

Could someone please tell me what happened there? What manner of metathesis did I commit? Is it properly metathesis? Is it actually more complicated than that? This inquiring mind would love to know.

Thank you!