Remoraid evolving into Octillery is seriously weird, yeah! Samurott is pretty odd as well - his design is great, but it isn't at all congruent with the rest of the line.
I think the weirdest thing I've seen in Pokemon, though, is Garbodor's speed stat. He has a base speed of 75, which means that he can outspeed a decent number of Pokemon, including Luxray. Let me reiterate: in Pokemon, a bag of trash is faster than a lion!
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[NO BARKLEY NO PEACE]