According to lawsuit papers, Charles Armstrong -- Prez and CEO of Armstrong Interactive -- filed trademark paperwork in January for "Double Dare" ... months before Nickelodeon aired the reboot of the show on June 25.
Viacom admits in the paperwork it let its trademarks for "Double Dare" expire in 2001 and 2002, but claims it has continuously used the name since the show's debut in 1986 for TV programming, live events and merch ... therefore, it never lost the rights to the name.
The company also claims Armstrong has a slimy history of squatting on classic kids' TV titles in an "illegal scheme" to "exploit the goodwill of other popular shows" ... including "Wonderama," "Kids Are People Too" and "Romper Room."
Armstrong sent a cease and desist letter to Viacom in May, warning the media company that if it went ahead with its relaunch of "Double Dare" ... it would be doing so "at its own risk" of legal action.
Viacom aired the reboot anyway and is now suing Armstrong to get a judge to declare that "Double Dare" belongs to Nickelodeon.