Title text: The rest is fear of raptors.
The Swiss Family Robinson is a novel by the Swiss pastor and writer Johann David Wyss. In the novel, a shipwrecked family builds a tree house as good as a normal house complete with library and mechanical contraptions.
Growing up, many children grow a fascination with tree houses. Tree houses are a child's own special place to do stuff away from their parents, have some autonomy, perhaps form a club. The obsession with tree houses usually fades once a child reaches his teenage years, but of course some of us never grow up. Being an adult geek/scientist who still enjoys childish things, Randall wants to build a sophisticated tree house rather than a simple one, taking the theme from above mentioned novel.
The title text makes reference to the regular xkcd joke about how terrifying Velociraptors from the movie Jurassic Park are. But they never can reach a tree house, just because it's too high as you can see here 87: Velociraptors. "Raptors" might refer to the informal bird group, hawks and owls and such. A joke relying on the pervious infatuation with velociraptors.
- [Picture of Brain. Line points at a highlighted point.]
- Section that is devoted, no matter where I go in life, to planning the ultimate tree house*.
- *Oh man, it would be like Swiss Family Robinson, but with multiple trees connected by... hey come up to my room and see the blueprints!