Luigi ran at the black suited speedster and punched it, getting its attention, he ran away from the city where he or that thing can't accidentally hurt anyone. The black speedster chased him into open fields and across deserts, Luigi kept running with only one thing in mind: get away from that thing, for the first time since he became the flash Luigi was scared, sure he could take on the reverse flash, an evil version of himself and other meta humans but this one scared him, this thing wasn't even alive, it looked like a zombie with its decomposing face in which some parts of the face you could see the bones of its mouth and lack of nose and black lifeless eyes.
Luigi stopped, scared as the speedster closed in on him, he dodged a grab and a punch and was throwing his own back at it, throwing it into trees and punching it or the other speedster doing the same, but Luigi wasn't quick enough to dodge the next grab at his throat. His vision was fading and before he could pass out he saw the young boy running up to him
Back at star labs the young speedster watched the black speedster chase Luigi. "That thing is going to kill him." He said nervously. "You don't know the flash kid, he gets everything done quick." Said Mario. "You don't know what that thing can do, I need to help him before it kills him." He sped off after Luigi.
When he got there he was met with a horrible sight, the speedster wraith was chocking Luigi but that wasn't the worst part, its touch mad his skin turn aged and old and the suit looked like chipped leather, he had seen this before, the time wraiths grab their victims and then they age them to dust to be taken to the speed force, now having a time wraith was bad enough but to have one in the form of a speedster was just even worse on so many levels.
He ran at it at top speed and dropkicked it off Luigi, Luigi's face and suit turned back to normal and then picked Luigi up onto his feet. They both ran at the speedster wraith and tackled it to the ground and Luigi phased his hand into the black speedsters heart, only for it to not do anything but make the speedster scream that terrible scream. "it doesn't work like that flash, it's not a living thing, it's a time wraith in a speedster form created by the speed force, normal death such as old age doesn't really work since our cells regenerate so rapidly it expands our lives, you could be 80 but still look like you're in your early 40s."
"And how do you know all this? I thought you couldn't remember anything."
"I guess speedsters recover from amnesia just like how we can heal fast." Said the boy.
"Ok what do we do about this thing then?" asked Luigi.
"we got to throw it back into the speed force."
"How do we do that?"
"We can open a portal to it if we run fast enough we should be able to do it."
The boy starts to run in a big circle and Luigi runs with him, in about a minute a swirling blue and white portal opens up and they throw the wraith into it, when they did the portal closed.
"I never want to see that black flash ever again." Said Luigi.
"Why did you call it black flash?"
"Well I already have someone called the reverse flash, I call him that because our suit and lightning color is inverted so why not."
"Makes sense I guess."
"Now what is your name?"
"I am Michael, Michael Mario. Your son from the future."