xkcd #3303: Slab Graveyard

Title text:

It's ok if you want to close close your eyes for the slab graveyard, so you can still have fun riding the mantle plume back up afterward!

Transcript:

Transcript will show once it’s been added to explainxkcd.com

Source: https://xkcd.com/3303/

explainxkcd for #3303