Question

One morning I shot an elephant in my pajamas. How he got into my pajamas I'll never know.

what does this mean

Answer 1

 One morning I shot an elephant in my pajamas. How he got into my pajamas I'll never know.

Take advantage of the fact that the same sentence can have two different structures. This famous joke from Groucho Marx assumes that most people expect the structure of the first part to be

One morning [I shot an elephant] [in my pajamas].

But another possible, and perfectly grammatical, reading is

One morning [I shot] [an elephant in my pajamas].

Answer 2

a small toy elephant had been seen at my pyjamas. and he don't know how he get into his pajamas