There were a few possible captions for this, my boyfriend really likes this and we had alot of fun with this while on the train. A few possible ideas:

"..And then they went up a platform and we never saw them again.."

"It was THIS BIG! I swear it!"

"It wasn't easy y'know, fighting cancer!"

"They're called free-radicals, I think they're kind of like hippies, but they eat your toes while you're sleeping!"