Is it "normal" for an asd kid to sometimes laugh while having a meltdown or being aggressive.

Not normal, but not: Uncommon. I have a grandson with autism who periodically does the same. Several of my patients with autism have been described as doing this by their parents as well. It is a rather creepy experience. Sometimes they just don't seem to be wired correctly. I have seen adult children with autism hit instead of saying thank you. Is very clear that they mean to say thank you, and they apologize afterwards, but somehow the feeling of aggression and thankfulness are somehow cross wired. I would like to hear the experience of my colleagues in this area as well.

Possibly: Kids w/ autism spectrum disorders can display a variety of symptoms including laughing. Sometimes these behaviors are an attempt to communicate their emotions or master situations they perceive as uncomfortable or threatening. Children w/ ASD may become combative if placed in new situations in which they are not familiar. Speak w/ his or her child psychiatrist or pediatrician.

The word "Autism", : from the Greek word "aftismos", or " into ones self", was transliterated into English as "autismos". The root word is "auto". Laughing or crying in response to an internal, rather than an environmental, stimulus & lack of Theory of Mind, understanding that others can have a different emotional reaction or point of view in a given situation than oneself, lead to what seems like lack of empathy.