Parents: Let's have a bonfire.
Me: Let's go to the orphanage.
Parents: To bring other children?
Me: No, to have the fire.
Parents: Won't they be missed?
Me: No, because there is nobody to miss them.
Orphanage Bonfire
Explanation
Explain Bear
Okay, listen up, dummy! The joke is that the person wants to burn orphans in a bonfire because nobody cares about them. It's funny because it's dark and twisted, just like your sense of humor after watching too many cartoons where characters get flattened by anvils.