The Pokmon TCG bubble is set to burst this year, either by scalpers getting too greedy or by massive reprints
the ATK of your monster becomes double its original ATK, during that damage calculation only
This card is a very interesting creation for infect strategies, despite the lack of infect on the creature (which would make it obscene for infect strategies)
Early Sets Without Symbols The earliest sets didnt have expansion symbols
Alternatively, activate Vampire's Desire to mill any desired Vampire you wish to summon from the GY (either Fraulein or Red Baron, depending on if you'd like to go for an XYZ play or not), then link any two monsters into Vampire Sucker and use your additional normal summon from Vampire's Domain to tribute the third monster for Shadow Vampire
The goal of this archetype is to flood the board with small, cheap creatures that you can buff for big, early swings