Kids that are very weird and immature. They have a strange attraction to sets of stairs. They hang out there all the time.
Person 1: Bro who are those kids hanging out at the stairs?
Person 2: Stair kids bro
Person 1: WTF is that one doing?
Person 2: Looks like he's hanging upside down from the stair railing.
Person 1: Let's leave. These stair kids are creeping me out.