Glenn Jacobs is approaching 23 years with the WWE and most of those have been under the moniker of Kane. The Big Red Machine made his debut in 1997, but Jacobs had a couple of earlier gimmicks in the mid-90s, most notably Isaac Yankem and "Fake" Diesel. The former of those two was the prototypical cartoonish gimmick of that time period and it fit right into the New Generation Era. Recently Jacobs appeared on Chris Jericho's Talk is Jericho podcast (h/t Reddit) where he detailed what Vince McMahon had in mind with Isaac Yankem, DDS.
Jacobs talked about being brought to WWE headquarters in Connecticut via limo and he said he felt like he was on top of the world. When he met McMahon, the first thing the WWE Chairman told him was, "Well, have you ever been afraid to go to the dentist? I've had this idea for a dentist character and I think you'll be perfect for it!"
As McMahon explains the Isaac Yankem character, Jacobs is struggling to keep a straight face as he realizes that WWE brought him to Connecticut just to tell him he's going to be a wrestling dentist. But Jacobs made the most out of the gimmick, and even though it lasted just a few months, it would start a relationship that would last over 20 years.
If you remember, Yankem was billed as being from Decatur, Illinois and Jericho said that everytime he drives past Decatur he takes a picture of the town sign and sends it to Jacobs. It's clear that Jacobs wasn't a huge fan of the gimmick but he made the best out of a bad situation (and at least it was a better gimmick than Fake Diesel). Even 20 years after the Yankem gimmick ended, Jacobs is constantly being reminded about it because retro action figures were recently made of Isaac Yankem, and fans request autographs on the rare memorabilia.
Kane last appeared on WWE TV on the Raw after Royal Rumble in which he last a Last Man Standing Elimination Chamber qualifying match to Braun Strowman. That may very well end up being his final match as Glenn Jacobs is currently in a campaign to become mayor of Knox County in Tennessee. Election day is May 1, 2018 and Jacobs said that if he wins and becomes Mayor Jacobs, then that will be the end of his in-ring career.