Araquanid is an interesting one. If you looked at its stats it would be rather unremarkable. A great special defense stat but nothing else that makes you think it's anything above average. And just like similarly perceived bug type pokemon such as Galvantula or Leavanny, it gets access to one of the best moves in the game in Sticky Web.

Sticky Web is an entry hazard like spikes or stealth rock, but unlike its brethren it does not cause damage when your opponent switches a pokemon in. Instead, it will automatically lower the speed stat of the incoming pokemon by 1. In a turn based battle system, the speed stat is widely considered to be the most important one. With Sticky Web on the field, you can then use other destructive offensive pokemon normally held back by a mediocre speed stat to actually outspeed and K.O. everything in your path.

This niche in itself would give Araquanid a good score, but then you look at its ability. Water Bubble is a signature ability to Araquanid, and it is incredibly broken. It gives you not one, not two, but THREE abilities in one. First of all, it makes you immune to burn (such as the ability Water Veil). It also halves the damage you take from Fire moves (like Heatproof), essentially giving Araquanid a fire resistance. And if that wasn't enough, it also DOUBLES your water type damage. Just a straight up x2 multiplier to damage. Add this on top of your x1.5 multiplier from being a water type pokemon and your average attack stat does not matter anymore. Absolutely insane. Of course Araquanid is still held back by its other stats, which prevents it from being broken, but it is a very clear threat in its own right.

I'd give it an 8.5/10

Since he just got a mega evolution, Dragonite is up next