No matter how anxious or fearful Bowser happens to be, he needs to be groomed on a regular basis. It not only helps keep him looking his best, but it lets you inspect him for mats, tangles, fleas, ticks, cuts, scrapes and any other sign of injury. Most dogs become anxious for more than one reason, it could be that they were badly scared as a pup or have been injured or mistreated by another person. If the only time Bowser seems to be anxious is when the time comes to groom him, it could be that he has had a bad experience at the groomer's.
Trying to groom an anxious dog can be a lot like trying to grab a one of those old windup "Mexican Jumping Bean" toys that bounced all over the place. The more anxious Bowser is, the more challenging grooming him can become. Fortunately, the more time you spend working with your dog the less anxious he will become.
Anxiety can be a bit challenging to deal with at first. Your goal is to first work with your furry friend to help him overcome his issues and find a way to get him to relax. Eventually, after you go through this process over a period of grooming sessions he should finally see the whole process as enjoyable rather than scary.