Kilroy
noun
Kil·roy
ˈkilˌrȯi
plural -s
: an inveterate traveler
like the roamers Kilroy and Ulysses
Peter Viereck
Peter Viereck especially : a transient soldier
of all the Kilroys of history who have passed through here … it was Napoleon who best summed up the strategic importance of Malta J. P. O'Donnell
J. P. O'Donnell 
Word History
Etymology
after Kilroy, mythical soldier of World War II whose name was inscribed in unlikely places all over the world by American soldiers