These encapsulate the 70s so wonderfully for me.
Must have.
"You set up the refillable tank with the city scene and a container that holds tiny Hulk. We'd say Bruce Banner, but he's not. He's just tiny Hulk. Then you add water and watch as Hulk hulks his way out, bursting through the "container" over a two day period and growing to full size in 5 days. It's like a very slow motion, controlled Hulkout, which is the best kind. And when he's done, just drain the water and repeat ad infinitum."