A/N: This crossover might be the funniest thing I've ever seen bUT THIS MOMENT BROKE ME OK OH MY GOD IT HURT
Barry was waiting in the next room when he heard the familiar sound of a breach opening, followed by a startled squeal from Felicity. He ran inside, calming a bit at the sight of a familiar face, if not a familiar suit. "Jay?"
The other Flash stared at Barry, seemingly caught off-guard. "N-no."
"Oh my god." And Barry knew it was too much to hope for, but the word spilled out anyway, quiet and heartbroken and hopeful. "Dad?"
"Barry," he said, his voice breaking as he took a hesitant step forward. "You're alive in this universe?"
Barry stepped past Felicity and Diggle, hardly noticing the tears beginning to slide down his cheeks. "And you're alive in yours," he rasped.
Simultaneously, they moved forward, closing the gap and wrapping each other in a tight hug. Barry buried his face in his dad's shoulder, closing his eyes and clutching him like he was a scared little kid again. Dad enveloped him in his arms, pressing a kiss to the top of his head. "God, I missed you, kid."
"And I missed you," Barry whispered.
And for a moment, for just a moment, everything was all right again.
"Barry," Oliver murmured.
Barry forced himself to step back, swiping at his tears. "Right. Reality is screwed. You didn't come here to hug me."
"Later," Dad promised, leaving his arm around Barry's shoulders. "We'll catch up later, son."
-EW-
"Enough! You will not do to this Earth what you did to mine."
"I admire your persistence, Henry," Monitor said.
Lightning flared around his dad, and before Barry could blink, he was running.
Monitor lifted a single finger.
In a cloud of blue smoke, he disappeared.
"No!" Barry screamed, starting to run forward, reaching for an arrow. "Dad! DAD!"
But Oliver and Kara caught him, stopping him. He struggled, tears streaming down his face, but in the end, all he could do was repeat "Dad," over and over again, each one more broken than the last.
"He's gone, Barry," Kara whispered. "He's gone."
He sank to his knees, clutching his friends like he had clutched his dad mere minutes ago.
And later never came.