there are at least 3-5 documented swimmers attacked by pike in Wisconsin every year. The Northern Pike has a really small brain, a large appetite and a row of sharp teeth. their only instinct is to bit what moves if it is about 1/3'd its body size, they usually eat it.
They start 'em young. I was trying to find the pick where one pike fry was trying to eat another the same size taking him head first. This pick isn't it, but it works. BTW, I'd love to fish for big cats. I like the fight more than anything......
I caught a 12" pike one time trolling a 13" Grandma bait. Probably dragged it around the lake for an hour and never knew it was there until it was time to pull the lines!