There are two things I would do if I saw a Beedrill: either run like my life depended on it (and it would) or freeze on the spot and never move again. I hate wasps, even the little one. So a 3 feet tall wasp with giant needles? That's nightmare material right there.
I'd have a similar reaction if I saw an Ariados or a Galvantula, and to a lesser extent, Spinarak or Joltik.
... Actually, there's not a single Bug-type Pokémon I'd like to meet in real life.
Of course, there are also the one like Dialga/Palkia/Giratina/Zekrom/Reshiram/Kyurem/Groudon/Kyogre/Rayquaza/Regigigas, for obvious reasons.
But I think my second choice after Beedrill would be Darkrai.