Answer: Blue Stragglers
In 1953, the astronomer Allan Sandage measured the intensity of the stars in the global Messier 3-star cluster (if you are a fan of constellations, this star cluster is in the northern constellation of Canes Venatici). Sandage observed a rather peculiar event in our own secret backyard, the Milky Way: stars that seemed far far younger than their closest celestial neighbors. How can these few rogue stars become so blue (an indicator of higher temperature and hydrogen content and hence younger age) compared to their neighbors, who probably formed at the same time?
These stars retain their youthful appearance much in the same way as the vampires in the human legend: by seeping the energy of their companions. The two most viable theories on how this happens is that the stars are paired as binary stars and that one slowly delivers the other, or that they are current or past binary stars that are in the process of merging or already doing so. Either way, it is obvious that there is some form of transfer from some stars to nearby stars. In dense areas of clusters, especially in the nuclei of globular clusters, there are dozens of these blue jets, quietly pulling hydrogen out of their neighbors and, in fact, extending their own lifetimes at the expense of the stars they are fed.