Karen has struck again -- this time at a park where a few little kids were taking a Power Wheels toy car for a spin ... and she was ready to pull 'em over.
Check it out ... the old lady -- who one Twitter user hilariously dubbed "grandkaren" -- is upset that the woman watching the children is letting them "drive all over the place."
When the woman says the kids are just playing in their toy vehicle, Karen says she's never seen a car in the park before ... and what really bothers her is that they don't have a driver's license.
Again, this is a Power Wheels ride ... which has a TOP speed of 5 mph.
Grandkaren gets one last gripe in about the kids being unsupervised ... by the woman recording them from yards away.
It's unclear when and where this vid was shot, but regardless ... it's incredible stuff.