Viking is an activity, or an epithet for those who carried on in that manner--pirates, or freebooters. The enduring legacy of Scandinavian invasion was the Danish invasion of 866, although it was not completed until 1013, when the Danes took over all of England. They didn't keep it for long, though.
Danish has mostly survived in place names, and, rarely, in given names. The Romans built an administrative center in the north of what is now called England, and called it Eboracum. The Saxons called it Eoforwic, which the Danes corrupted into Jorvik (pronounced yor-vic) and that has become York. Most of the Danish placenames are in the north and the midlands. The suffix -by
, for example, means a farmstead, as in Grimsby. A village would grow around the farmstead of an influential Dane, and soon you'd have a town with a name ending in -by. The name usually consisted of Dane's name and the suffix, as in Grimsby. Other suffixes which are common in that part of England are -thorp, -twaite, -wick and so forth.
This echoes what happened when the Saxons came. The suffix -worth or -worthy means a fortified manor house, and -tun or -ton (and later -town) means a fortified settlement. So, Glastonbury "the fortress at the fortified settlement of Glas"--when Glas was the original settler, and the settlement was fortified, and later a burh or burgh (prounounced the same) was built on the orders of the king of Wessex. The extreme example of silly place names is Torpenhow Hill, which means hill, hill, hill Hill. Tor is Brythonic for hill, Penn is Goidelic for hill and how is a corruption of a Norse word for hill.
Language is fun, speculating on what mythical aliens might do is boring.