I saw a sentence like:
- "Behind me lies a dog."
It has peculiar sentence structure in order of "Prepositional phrase" + "Verb" + "Subject".
What is this called? And when is this used? And could you explain me whole concept of this?
That is subject-dependent inversion, which is an information packaging construction where the subject is switched with an internal dependent of the clause.
For your original example, the usual canonical ordering would be something like:
which has Subject-Verb-Dependent order (or S-V-PP order).
With subject-dependent inversion, it becomes:
which has Dependent-Verb-Subject order (or PP-V-S order).
A writer will often use subject-dependent inversion when the subject contains newer info than the info that is contained in the fronted dependent, or when the fronted dependent is a locative expression (e.g. "behind me"). We often prefer to have the newer info at the end of a clause or sentence, and have the older info at the front (which is usually the subject slot). Locative expressions are often moved to the front in order to help set the setting for the rest of the sentence.
You'll find this type of construction more often in edited prose than in informal writing or casual speech, because it usually takes some editing effort to apply this (subject-dependent inversion) to a sentence. Also, there are pragmatic constraints on when this type of inversion is acceptable.
For more info, there's the 2002 CGEL, pages 1385-90, "5 Subject-dependent inversion". For example, starting on page 1386, there's section "5.2 Pragmatic constraints on inversion", and its first paragraph is:
For inversion to be felicitous, the following conditions must obtain:
i. The preposed phrase must not represent information that is less familiar in the discourse than that represented by the postposed NP.
ii. Unless the preposed dependent is semantically locative, the inversion requires an appropriate open proposition that is discourse-old.
iii. The verb must not represent information that is new to the discourse.
And the discussion on these pragmatic constraints on subject-dependent inversion goes on for another couple of pages.
NOTE: The 2002 CGEL is the 2002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language.