“Pack the bags, we are leaving now.”
“Stop panicking, we are going nowhere.+
“I tell you we have to leave. They have landed in a big green sphere. I saw them put the periscope out at the top. I took a photo.”
“Looks like a gas holder to me.”
“You see, they are planning to gas us as well.”
“Just calm down, that building has been there for years.”
“I heard noises as I walked past. I am sure it is an invasion from another planet.
Jack found Mary was exaggerating. There were gas holders everywhere, although now a bit old fashioned. They had been there for at least 1,000 years, although Jack thought they were always there, all with labels advertising natural gas, which of course was a camouflage.
1,000 years was actually the incubation time for a Gronk, from planet Gronkle on the other side of the milky way and now they were ready. That night the sphere began to glow with a green fluorescence. The local fire service were called out and they turned on the hoses , but to no avail. By now the heat was at its height and the water had the effect of exploding the sphere.
The gronks emerged, thousands of them. Jack and Mary, like the remainder of the Earth people, did not live to see the next day and the Gronks had returned. The fruit of their excursion 1,000 years before had ripened. There are always exceptions of course. 1,000 years before a few Gronks were left on the earth to prepare for their arrival after the first invasion left and now they were organising. The earth was now inhabited by a carrot coloured hair population.