combination of the words barbie and barn.
a barnabie is a child raised on a farm who thinks she's as pretty as can be, hence the barbie part.

pronunciation: barn-uh-bee

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.