He rubbed his face against Adrien several times and then just stopped and stared at him. "Wait, Dad is here and he's real? And... Nope can't..."

He pulled away just enough to turn back into Gar, because certain things he just couldn't say as Spark.

"So... dad is here, wherever here is. But this isn't Nautilus or the train." He was trying to get his head around all of this. He looked at Plagg then back at Adrien. "Look, you come back onto the train with us and I will trade cheese for Plagg for fish for Spark. Or anything. Just... Just don't leave me again!" he begged. "Please Adrien."