Of being both retarded and rediculous at the same time. Or of being rediculously retarded.
having to pay taxes on tax is absolutely retardulous. Anyone who doesn't believe that their tongue will stick to a freezing pole and tries it just to be sure is completely retardulous.
Retarculous was originally coined by To Catch a Predator decoy, Emily Bicks. It is a conjunction of 'Retarded' and 'Ridiculous.' It is used to describe something that is extremely dumb, stupid, etc.
"Trying to use a trash bag as a parachute is absolutely retarculous."