A squid is a young male, who owns a powerful sports motorcycle and rides it as follows:
- Far too fast on public roads 
- Likes to perform stunts like wheelies and stoppies in traffic
- Wears as little as possible, like t-shirt, shorts and sandals with no helmet.
Squid is supposed to stand for Stupidly Quick, Underdressed, Imminently Dead.
This is what happens when you are a squid and don't perform basic maintenance on your bike:
Just thought you'd like to know.
This dude, on the other hand, is just some normal guy enjoying a bit of off-road fun and saving wear on the front tyre:
And NOT a squid.
 I ought to clarify that. When I say far too fast on a public road, I mean 60 through town traffic, or 105 between lines of cars on the freeway. In my slightly anarchic opinion, there is no such thing as 'too fast' - there is only 'too fast for the conditions'. 20 past a primary school at 3.30 pm may be too fast. 150 on an empty motorway may be just 'making progress'.