Grey Banana W/O lights or sound

It's been a while since this occurance but the craft is still very clear to me. I was 12 years old. It was nearing sundown,the sky was overcast, on Woodlawn Ave. near the SW corner of the city. Four or five of my friends  (I can only remember [name deleted] being one of them)and I were just playing "Tag" or some other game we played outdoors, when one of the guys started screaming like a mad man. His eyes were poping out of his head.I was facing him and ducked because he was looking and pointing behind me like something was going to hit me in the head or something. I spun around and did'nt see anybody close to me. But within a second or two it caught my attention. There in the sky was an object which looked to me like a "grey banana" with the ends pointing up, and rocking to-and-fro on it's bottom arc like a rocking chair. We wathced it for 30-45 seconds then we took off. It was hovering low, Im guessing 3-4 hundred feet in altitude and 75 or 100 feet across point to point and 25 feet or so in diameter with no lights or sound at all. We all ran as fast as we could to ((deleted--neighbor's)) house looking back as we ran. It seemed to be following us, so we all went sliding under his dads pickup truck. ( I think we followed the leader to get away from it.) We were there for a good half hour's time because nobody had enough guts to look to see if it had gone. Thankfully it had by the time we came out. I get the EEBEE JEEBEEs so bad when I think about it. Goose bumps and all. I've only told my wife about it. I'm 47 years old now and this is still the most vivid memory of my life so far!
Date is approximate.  PD