You are being hacked, personally.
What do you do with a hacker? Leave them them a trojan in the golden french fry.
And just like dealing with a hacker you can't go all obvious about it like having an excel spreadsheet names passwords... subtlety is key and then manipulation is returned.
I chose the nickname blankip for SE because of dealing with an exact situation.
I was working with another manager in our NOC. He was a fishing buddy of the VP. He had no tech skills at all and have low intelligence. But he talked a good game and loved to take credit from anyone around. I found myself giving him bites to discuss at our weekly management meeting. I am not an overly jealous person nor do I like politics/brown nosing so when he said word for word what I was telling him as his own words to management I still had to say, "Dude didn't I just say that to you?" He would usually answer, "I just wanted them to know about OUR conversation. You are all good."
Well I took a two prong plan, that I suppose would work for you too:
1) Build up his bad ideas to him. Make him think they are genius. If he uses your name, clearly act like he didn't understand you right or you didn't agree.
2) Slowly introduce bad ideas and let him take them over. Subtlety is key. You cannot be obvious. Let the evil genius in you shine. Again, he misunderstood you because he doesn't really understand.
So the story goes... It was 1999 and we were a young but large network company. We were transferring from old equipement to new edge routers and getting our dark fiber connected. Lots of sessions on transfer speeds, BGP, reducing hops and so on. This manager was freaking clueless.
Let's call him Brian (which may be his real name). Because Brian knew nothing about networking, when we started a new security team he thought he should have a say in it or even manage it. We had a few test beds hacked and as a team we were trying to think of different security measures we should have in place for our Hosting accounts (we had major sites we were hosting).
I tried a few things to give to Brian that were ridiculous, but nothing worked because he didn't understand what I was saying. Then one day Brian came to me with an IP range that was getting prodded heavy. Jockingly I said, "Well Brian no one can hack us if we give the servers blank ips." He thought it was genius, revolutionary. After 10 minutes of us talking he walked away with a huge shit-grin on his face. I was elated.
Couple days later at our Thursday weekly we have us an 20 other managers (most way more senior and all super technical). When asked about an update on new security implementations I started talking about our servers and even started alluding to address allocation (yes I know this means nothing to security) and I knew Brian thought I was jumping his idea. The next 5 minutes were the most magical 5 minutes I have ever seen at a meeting. Brian went on about giving the servers blank ip addresses and they would be impossible to hack. I can't even remember half the crap he said because half the room thought he was joking and the other half was in shock.
After he was done his buddy realized not only that his friend was a moron but he looked like a moron for hiring him. The VP cut him off at a point and said, "What the fuck are you talking about? Please shut up." Brian was fired a week later. His boss went off on me the next day saying that I made him say that stuff. Word got around office eventually - me I said nothing. I honestly believe that upper management was so impressed with my manipulation of Brian that they promoted me early. Who knows?