The assault was thought to be a random attack, with police describing it as "terrifying" and the worst assault they have seen.
"He strikes him to the point he's unconscious, hovers over him and appears to taunt him," Detective Senior Constable Matthew Coleiro said.
"Once he regains consciousness he again continues the assault until he's unconscious again, hovers over him again, then leaves him in the middle of the road unconscious."
The 32-year-old eventually regained consciousness and walked towards a main road for help, where he was found by a passer-by almost half an hour after the attack happened.
"It appears to be unmotivated at this point, the victim is seen quite clearly stepping off a tram walking on his own, this unknown male runs up to him and we don't know why at this point," Senior Constable Coleiro said.
"The vision is very confronting, we're only releasing parts of it."
The victim, a travelling musician visiting Melbourne, has required two surgeries since the attack to stop the bleeding on his brain, as well as for a broken jaw.
He was due to fly home on Saturday after spending six weeks in Australia.It is alleged that this is the scum, Enea Myrteza, who attacked the American.
Scum number 2, the cat thrower, Cheng Lu. In an extraordinary decision by Magistrate Costas Killias, he dismissed the charges of him throwing a cat off the 45th level balcony of a city apartment building. Apparently you can accidently throw a cat off a balcony.
Magistrate Costas Killias on Tuesday dismissed charges of animal cruelty and reckless endangerment against Mr Lu, finding the university computer sciences student threw the cat over the balcony but had no criminal case to answer.
The only comfort is that that the internet does not forget things like this. Both will be forever damned.