Ariados 1999-2019
>Gen 2: early route weak bug with a cool design. Gets Spider Web (a bug type Mean Look) as a signature move
>Gen 4: Gets the new Shadow Sneak and Sucker Punch to make up for its horrible speed, and the new Toxic Spikes for some utility
>Gen 5: Gains Sniper, its hidden ability
>Gen 6: One of 6 lines to get the very useful Sticky Web, also gets Rage Powder and Megahorn as breeding moves
>Gen 7: Given a stat boost, given Focus Energy to work with Sniper, and Swords Dance on evolution, also a new new signature move in Toxic Thread that allows it to to post on /vp/
Someone in the Game Freak office clearly loved this thing and lobbied for it. I can't think of another pokemon that got given more useful additions as the generations went on. It may be untiered garbage on Smogon, but I love it, some guy in Game Freak love it, and it will go this gen without some boost to keep it interesting. RIP in piece, buddy.