Avengers (1963 1st Series) #295

"Beggars Would Ride!" Part 2 of 4. Script by Walt Simonson. Art by John Buscema (layouts) and Tom Palmer (finishes). Cover by John Buscema and Tom Palmer.

Ravonna plucks a giant mechanical dinosaur from the time stream and sends it to attack Washington D.C.! Once Doctor Druid becomes aware of the Mechanisaurus Rex in the nation's capital, he sends the Mighty Thor to intercept it!