The scene where the lice emerge from number 5's hat and the preceding scene where the kids enjoy nachos, spoof the scene in Alien when the chest burster emerges from Kana's body, albeit toned down drastically from the movie
the lice infecting the tree house are reminiscent of the xenomorphs infesting the colony on lv-426 in Aliens, and the pink lice at the climax is a spoof of the alien queen, other parodies include the kids taking the roles of the colonial marines, number four=hudson number three=vasquez, number one=possibly bishop, number five= ripley,