In [S] collide there was a huge reference (reference might it an understatement) to undertale in the fight between davepeta and LE. Could you tell me how Hussie was able (legally) to use it? (I mean) what is the connection between Homestuck and undertale?

Toby Fox and Andrew Hussie have been friends for years. Toby been making music for Homestuck since the beginning (he even had a song in the flash), he also started creating Undertale in Hussie’s basement