I probably missed a trick or two but here goes nothing at 39 chars 
sub gapify_lk {
  $s=shift;$s=~s/(.*-)?.{$_}/$&-/for@_;$s
}

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"Argument is futile - you will be ignorralated!"

In reply to Re: MeowChow Golf challenge -- Adding gaps to a sequence by larryk
in thread Adding gaps to a sequence by ariels

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