Popcorn, either as an edible explosive or semi mindless entertainment. KnitNan
The human had hung up a hand-made sign - Explosive food preparation in progress before they produced a device and a package of dry, yellow seeds.
"Your pardon, cogniscent An'dee?" said Plyq'ix. "What is meaning, 'explosive food'?"
Andy had a very simple explanation. "It goes bang."
"Surprising bang. Harmless, but surprising."
The machine whirred into life and the grains poured in. For a while, nothing much happened but rattling and whirring and then...
Small explosions of the kind meant to drive off evil spirits in the superstition times. At first a few, then a rapid succession of them.
Knowing the ways of humans, Plyq'ix had been expecting something a great deal more hazardous. This was the same species that had tenderized meat by firing it through a cannon.
"This is not worthy of warning sign," said Plyq'ix in vague disappointment. Even the white objects seemingly foaming out of the device were disappointing.
"Better to be safe than sorry." Andy shrugged. "Last time I made popcorn, I nearly killed someone."
Now that sounded human.
 The Mythbusters have left a lasting impression.