Why does Robin (season 1) laugh maniacally?

He laughs like that in order to scare the villains and I mean who wouldn't laugh if your about to do something like run in the rafters and hack into a few devices.

Robin's laugh(and as far as I know dick was the ONLY robin to do it) is the main element that shows he is going to engage inva fight, although he sometimes does it to distract enemies.

It's for dramatic entrances and besides its pretty cool

Robins, the birds, are known for their cackling, degrading laugh. The Robin in this mostrar is known for his sarcastic nature, so the laugh just complements his personality and alias.