WordNet (r) 3.0 (2006):

bob up
    v 1: originate or come into being; "a question arose" [syn:
         arise, come up, bob up]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "bob up":
   accomplish, achieve, appear unexpectedly, approach, arrive,
   arrive at, arrive in, attain, attain to, be received,
   be unexpected, blow in, break forth, break water, burst forth,
   check in, clock in, come, come in, come to, come to hand,
   come unawares, come upon, creep up on, debouch, erupt, fall upon,
   fetch, fetch up at, find, flare up, flash, flash upon one,
   float up, fly up, fountain, gain, get in, get there, get to, gleam,
   gush, hit, hit town, irrupt, jet, jump up, leap up, make, make it,
   pop up, pounce upon, pull in, punch in, reach, ring in, rocket,
   roll in, shoot up, show up, sign in, skyrocket, spring up, spurt,
   start up, surface, time in, turn up, upleap, upshoot, upspear,
   upspring, upstart, vault up