derived from spastic originally then spacker then spackattack its when someone has a spasticated attack like a epileptic fit only there not epileptic when someone decides they are going to act really really wierd and dance in funny ways or say stupid things they are having a spackattack
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.