SirFrozenFairy said:
The best I can recall is Daisy using a Cellular Shopper to buy a Cellular Shopper in Mario Party 3. Wasting 5 coins. I've seen it happen on more than one occasion. I've also seen the AI buy a Skeleton Key and then throw it away the next turn for seemingly no reason.
I've seen worse. The AI sometimes uses a cellular shopper, and exits out of the shop without buying anything.
Then it uses a Bowser Suit when no one is around them. They sometimes purposely land on Bowser when it's better for them to go the other way. I would understand it if they had 0 coins, but they never did. The AI also sometimes does chance time when they're in first and then screw themselves over by giving someone else the lead.
Those are just a few examples. I could write paragraphs on this thing, but I'm lazy.