The best replacement for stun is turn.

The best alternatives to stun are rated as following:
★★★★★  turn
★★★★  taser
★★★  flash mw2
★★  suppress
★★  flash mw3
★★  paralyze dragon nest
★★  knockaround
★★  snare
★  freeze diablo 3
★  drive stun
★  augmented camo
★  call of the haunted
★  seven tools
★  flash cod4
★  fiendish chain
★  dust tornado
★  solemn warning
  dry stun
  abyss sphere
  royal decree
  dark bribe
  solemn
  reckless greed
  abyssphere
  outbound proxy

Your alternative for stun is not listed? Suggest!
Speaking about stun, one probably shouldn't forget about sip.

Other search terms related to stun and their ratings are:
★★★★★ sip
You have in mind a companion for stun and it is not yet here? Propose!



Google Trends

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stun
turn
taser