This is the name given to the lance that pierced Yeshua's side as he hung on the gallows in John's account of the Crucifixion. The lance is mentioned only in the Gospel of John (19:31–37) and not in any of the Synoptic Gospels. The gospel states that the Romans planned to break Yeshua's legs, a practice known as crurifragium, which was a method of hastening death during a crucifixion. Just before they did so, they realized that he was already dead and that there was no reason to break his legs. To make sure that he was dead, a Roman centurion named in extra-Biblical tradition as Longinus stabbed him in the side.
'… but one of the soldiers pierced his side with a lance, and immediately there came out blood and water.' John 19:34
Here are two article about the alleged lance and its history:
1. Fulfills prophecy of no bone broken in Ex 12:46 and Psa 34:20.
2. "there came out blood and water". My wife, a nurse, explained the significance. As circulation stops, the plasma (appears as water) separates from more solid blood parts (appears as blood). John was giving evidence that the body of Yeshua was dead.
3. Not aware of any significance in Scripture of a lance. Even so, treating it later like the bronze serpent and calling it 'holy' would also be idolatry.
Real in the sense that yep, it would likely hurt if someone poked me with that.
Not real in the sense in that it appears to pristine for metal that would have been manufactured centuries ago.