Things just got a little more heated in the RIM / Kik dispute: RIM's now filed a Canadian patent infringement case against the company, just days after it pulled Kik Messenger from BlackBerry App World due to "breached contractual obligations." We don't have the complaint yet, so we're not sure exactly what RIM's patent covers, but it's a fair bet to say it's likely messaging-related -- and it's probably a safer bet to say that RIM doesn't screw around when it comes to dealing with potential threats to BBM. You mess with the bull, you get the horns.

Update: The complaint is out now, and it's a doozy -- RIM says Kik founder Ted Livingston was a former RIM employee who worked on BBM. When he left RIM claims he joined the BlackBerry Alliance developer program to ostensibly develop a music sharing app, but wrote Kik Messenger instead, using what RIM claims is confidential information from the Alliance program. RIM's also saying that Kik's marketing steps on the BBM trademark. That's a lot more than a simple patent issue, and it certainly explains why RIM reacted so violently to the app -- we'll see how Kik responds.