I met a traveller from an antique land
Who said—"Two vast and trunkless legs of stone
Stand in the desert . . .Near them, on the sand,
Half sunk a shatter'd visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed;
And on the pedestal these words appear:
My name is Ozymandias, King of Kings;
Look on my works, ye mighty, and despair!
“Mock” has a double meaning here: to create an imitation, but also to parody or critique, as the artist has done with Ozymandias. “The heart that fed [them]” refers to Ozymandias: the tyrant’s heart produced that “frown” and “sneer of cold command,” captured (“mocked”) by the anonymous sculptor. 
 Notice also that ‘the heart fed’. The heart is usually thought of as the seat of love. Here it doesn’t love and gives nothing, but instead takes or ‘feeds’ on whatever it needs. 
 Also, the heart represents emotion whereas the hand is mechanical.  This idea of balance, or lack of balance, may link to how Ozymandias abused his power and was uncontrollable.
Ozymandias