"The Cobra Strikes" is an enjoyable B-mystery, though I'll admit that the story is incredibly goofy and makes little sense. My suggestion is that if you watch it, you just turn off your brain and enjoy it as best you can.
The film begins with a scientist about to announce some big breakthrough to the press. But, as you suspect, he's soon attacked by an unknown person. Now at this point, I laughed...as the doctor at the hospital announced that the scientist has no memory and never will. How would he know this based on just receiving the guy in the emergency room??
At this point, a reporter (it's so OFTEN the reporter) gets involved with the case and the police do what they always do in these sorts of films...they let the reporter run the case!! Soon, lots of people are dying...and it is suspected that come Cobra Cult is behind the killings. Not surprisingly, there's far more to the story than that...and it's up to the reporter, with some minor help from the cops, to solve the mystery...eventually!
This film has every cliche known to 1940s mystery films as well as a LOT of silly twists. None of it really makes sense but because it is so goofy, I also enjoyed the film. Well made? Nope. Intelligently written, good grief no! But enjoyable despite itself.