Following on from last week's assignment, here is a story about Bill, the pregnant long distance lorry driver. Read on to see how it all turned out for him...

I had the character firmly in my head before I sat down to write the story. But despite that, he quickly developed characteristics that weren't there last week when I first met him. I suppose that's what happens as you get to know people better.

I hadn’t seen Bill for quite some time, but that wasn’t unusual. He’s a long distance lorry driver and he spends days, sometimes weeks, all alone on the road. But when he walked into the pub after a couple of weeks away I was surprised and a little bit shocked by the change in his appearance. For many years now, Bill has carried a huge beer belly proudly before him. But the man coming in through the door was a new, much more slimline Bill. Well, slimmer line anyway. He’ll never be a thin man, but his usual enormous, bulging waistline was now so greatly reduced that I almost didn’t recognise him. He spotted me and came over to my table.

"Hello Maurice," he said. "Mind if I join you?"

"Hi Bill," I replied. "Can I get you a drink?"

"A pint of whatever’s on tap," he said vaguely as he shrugged off his back pack and sat down. I went up to the bar to order the drinks.

"So," I said when I got back to the table, "looks like you’ve had the baby at long last."

Bill nodded and took a swig from his beer. For the last few months, whenever anyone made remarks about his rapidly expanding waistline, Bill had simply explained that one day he’d been driving his truck through the middle of nowhere, deep in the back blocks of the country. There he’d been abducted by aliens who had experimented on him. As a result of all that poking and probing he was now heavily pregnant. "I’m just a bit worried that it might have tentacles when it’s born," he would say, with a perfectly straight face. "It’s very hard to get clothes that fit properly when you’ve got tentacles."

Several of our more gullible friends took him at his word and there has been much speculation about the possible size, shape and colour of the baby in Bill’s belly. But I remain unconvinced. I’ve known Bill for a long time. We were at school together and I’m very familiar with his deadpan sense of humour. Back in 1969, when Neil Armstrong and Buzz Aldrin landed on the moon, Bill had taken me to one side and said, "Do you know the very first thing they saw when they clambered down the ladder from the lunar module onto the surface of the moon?"

"No," I said. "What did they see?"

Bill looked left and right to make sure that nobody else was within earshot. "There was a supermarket trolley," he said, "lying on its side just a few feet away from the lunar module. And it still had a receipt for a loaf of bread and a bottle of milk in it. Those things really do get absolutely everywhere. You find them in the strangest places." He shook his head at the wonder of it.

I didn’t find this revelation at all surprising. "I once saw a trolley perched at the top of a tree in the park," I said. "And there’s another one stuck in the alleyway behind the Post Office. It’s been there for months because nobody has been able to work out how to remove it. The entrance to the alley is far too narrow to push the trolley through. I wonder how the one on the moon got there?"

"No idea," said Bill. "Mission Control told the astronauts to keep it secret and never to point their cameras at it. So nobody knows about it except you and me. There was no mention of it in any of the public broadcasts."

I was struck by a thought. "If they are keeping the trolley on the moon secret, how did you find out about it?" I asked.

"I was listening to the live wireless communication between the moon and Mission Control on my dad’s ham radio," explained Bill. "The private channel that they didn’t pass on to the world at large."

I was completely convinced by his explanation and I only found out that he had been pulling my leg several days later when I mentioned the moon trolley to my physics teacher. He burst out laughing and told me I was an idiot. "Remember," he said, "it’s very easy to tell when Bill is teasing you. Just check to see if his lips are moving."

I asked Bill if he’d been having a joke with me, but all he did was wink and tap the side of his nose with his finger.

Ever since the incident of the supermarket trolley on the moon, Bill has been obsessed with astronomy and space-related things. He’s got heaps of books about it and he’s seen the movie of 2001 – A Space Odyssey at least a dozen times. So I wasn’t at all surprised when he started telling people that he’d been abducted by aliens. But I played along with his alien-induced pregnancy, for the sake of our friendship.

As I looked at the newly slimmed down Bill sitting beside me and drinking his beer I began to wonder just what the next stage of his little prank would be. He was going to have some explaining to do. "Tell me about your baby," I said, with what I hoped was a straight face. "Was it a difficult birth?"

"Well, it wasn’t easy," he said. "I’ve actually been in hospital for the last couple of weeks. They operated a few days ago, and cut the thing out of me."

"Ah," I said, nodding wisely, "a caesarian birth. I thought it might come down to that in the end."

"That’s one way of looking at it," said Bill. He reached into his back pack and pulled out a glass jar which he put down on the table. There, floating in a formaldehyde solution to prevent it from decaying, was a shapeless lump of pink flesh. It had clumps of wiry black hair growing on it, and the pale gleam of teeth could be seen lurking in a twisted, lipless mouth.

"So that’s what aliens look like," I mused. "I’ve always wondered. I’m glad to see that it doesn’t have tentacles. That’s one less thing for you to worry about."

"The doctors say it’s not really an alien," said Bill. "It isn’t even alive. They called it a teratoma. That’s a fancy name for a benign tumour which has rudimentary body organs growing in it. They’re reasonably common. My surgeon said he removes half a dozen or so every year. They can grow quite large, but nobody knows what causes them."

"You and I know what causes them," I said. "Clearly aliens implant them in our bodies. Stands to reason."

"That’s what I’m going to keep telling people," Bill said. "I’m having far too much fun with the story to stop telling it now. I’ll just have to be careful to steer clear of the inconvenient medical facts." He indicated our empty glasses. "Same again?" he asked. I nodded, and he took the glasses over to the bar.

I looked at the teratoma bobbing gently up and down in the formaldehyde. It really was remarkably ugly, and I felt quite sure that most of our friends would take one look at it and believe even more strongly in Bill’s silly story.

Then the teratoma smiled a snaggle-tooth smile, opened an eye and winked at me.