"Lightning danced across the sky" its an example of-

Personification: (ব্যক্তিরুপ দান)
- A figure of speech in which lifeless objects or ideas are given imaginary life.
- অর্থাৎ নির্জীব বা জড় বস্তুকে ব্যক্তিরুপে প্রয়োগ করার কৌশল।  
- For instance, when we say , The wind howled in the night.’’ We are giving the wind the ability to cry which is a human quality not the objects. Thus we have personified the wind in this sentence. 

Literary Example:     And Joy, whose hand is ever at his lips
        Bidding adieu 
        Here, Joy has been imagined as a living person. (Keats: Ode on Melancholy’)

Source: Oxford Dictionary and upcoming Content