@monkey123
It's an extremely meta joke. In the previous panel, they jump into the air, and in the first panel you linked, they land. They're making fun of those jump cuts in videos where you jump up and land somewhere else. That's why Beelzebub says "What was that just now?"
Wow, a sentient slime that can only communicate using Morse code via slamming its face against its wall and you give it an existential crisis for helping you, haha