Ledian
I hate this thing so much.
A few teeny changes could have made it... actually usable. It has similar BSTs to most of the other early bugs, but even Dustox is an upgrade on this thing. Its movepool is mostly only saved by Light Screen and Baton Pass... That's literally all it has going for it. It took an interesting design choice and did it so badly they straight up did a new LadyBug Pokemon which is much better (Orbeetle)! As a sick joke GF even gave it basically every Punching move AND had the gall to give it IRON FIST. WITH 35 BASE ATTACK.
The other mons with similar BSTs all functionally work better. Better offences (Kricketune, Ariados), better movepools (Butterfree, Dustox) or have had upgrades which give them new leases of life (Beedrill, Sableye, Mawile). Or even the mons with gimmicks all work better as well (Smeargle, Shedinja, Wobbuffet). There is just nothing going for it. I used it once on a team which included both Delcatty and Luvdisc, and it STILL managed to be bottom of the barrel in terms of usefulness... I could write a long essay on how badly it performs.
The only other mon which comes CLOSE to this level of disdain for me is Noctowl. For similar reasons for really. Outclassed by even Pidgeot, its also by far the weakest of the starter birds (And this includes the ridiculousness of Unfezant).