Something strikingly abnormal and/or strange.
Dude, Kyle Babbitt's clothes today are wacktacular!
Someone who is so lame
so bad, is so crazy in their head, that it has reached epic proportions.
"Mindy is totally wacktacular! Did you see how she was acting last night?"
Something or someone that is ultra or super wack. The act of being super ridiculous or obnoxiously stupid.
Person 1: Did you know the IRS had the nerve to only refund me $500 this year?
Person 2: Ugh.. that is completely wacktacular.
Person 1: Did you see the season Finale of "I love New York"?
Person 2: Yes. That girl, and all of those guys are wacktacular.
typically applied to online first person shooter multiplayer video games when an occurance during the game doesn't coincide with one of the players interest due to any number of reasons.
losing player could say: "That last game was wacktacular! The connection to the server was slow and my whole team was noobs