Archeops was brought up in another thread recently and it brought to mind something that struck me a short while ago, but at first while for the longest time I was confused by the disparity between Archeops and Carracosta as Unova's fossil duo in terms of stat build and the former being a high stat mon with a crippling ability while the latter is supposedly ordinary, the more I looked at them the more I realized there's a clear dichotomy between them in terms of how they are built, that they both end up being "do-or-die" Pokemon in opposite manners due to a certain aspect of them, especially when you account for Carracosta having the then-new move Shell Smash, and the idea that Shell Smash was designed with Carracosta in mind. I think it's a rather interesting dichotomy where they are designed on the same principle but in completely opposite ways.
Carracosta has rather average offensive stats of 108 and 83 respectively, and is very slow, but bulky with high physical Defense, and it has defensive abilities in Solid Rock and Sturdy which can either reduce damage from super effective hits or allow it to survive one hit with minimum HP. But take Shell Smash into account and it can reverse its initial stat build: with its initially poor Speed, it's almost certain to move second and take a hit as a result, but its abilities and bulk allow it to endure a hit and then use Shell Smash, which essentially doubles its offensive stats and its Speed, in exchange for lowering its Defense stats, in essence becoming faster and significantly more powerful after having been weakened and then firing powerful attacks from either side and ideally outspeeding its opponent before going down, its weakened Defenses and likely already being low on HP ensuring one more hit will take it down, but it aims to sweep before losing.
Archeops is on the other hand insanely fast and strong from the get go, with 140 and 112 offensive stats and a high 110 Speed, with inherently poor bulk to begin with. But while it can sweep and hit hard from the get go, hitting hard and fast, it has the ability Defeatist, which halves its offensive stats when its HP falls below half. Since Archeops is naturally frail, if it's not OHKOed by a move, it will almost certainly fall into Defeatist range from just one attack, which means it's also a do-or-die, except it's more immediate, and then loses its luster if it takes even one, the opposite of Carracosta in that regard, who needs a turn to get going and will take a hit first before boosting its own power in a pinch, whereas Archeops hits hard from the get go and then in a weakened state hits comparatively less overpoweringly hard.
I think there's a surprisingly interesting design theme going there in both cases, both around a unique do-or-die battle style, but in opposite manners. Carracosta revolves around a then-new mostly unique move to it, starting off with relatively unimpressive firepower but great endurance but boosting its Attack, Special Attack, and Speed in exchange for its defensive prowess, while Archeops possesses a unique ability and starts off with impressive Attack, Special Attack, and Speed, but will lose that if its loses over half of its HP, thus relying on keeping a high HP up.
Two sides of the same coin, if you will. A gimmicky as hell style in both cases but it's a surprisingly funny dichotomy.