Vikings were not fond of tattoos
Tattoos have been around long before the time of the Vikings. The modern portrayal of Vikings in movies and TV shows would often depict Vikings being covered in tattoos and ancient symbols.
Source: Herald Weekly
But the truth is, the Vikings were very clean people. It is unlikely that they would cover their bodies with something that they can not wash off. Although it is a trend now for those with Viking heritage to get what they consider traditional Viking tattoos.
Vikings got high before they went into battle
Just like some people would use steroids before playing sports or doing physical activity, the Vikings actually used natural enhancements like mushrooms before going into battle and it would make them insanely strong and vicious.
Source: Herald Weekly
They believed these enhancements helped them have supernatural strength.
But of course, in reality, they were just getting high. Apparently, the Vikings loved that psychedelic feeling. Historians believed that the Viking warriors loved getting high because most of them had mental health issues from all the battles and raids they have been in.