It’s a reference to the slogan of 80’s wrestler Hulk Hogan, “Whacha gonna do when Hulkamania runs wild on you.”
Hulk Hogan also made a video for the Penguins to use when Geno scores. There’s also a weird hockey-wrestling thing where a lot of teams started getting wrestlers to do these videos, and it seems like a lot of hockey fans grew up watching/still watch wrestling.
There is also a Penguins fan named Cy Clark who dresses up as a Hulk Hogan look alike for games and people call him Malkamania.
Cy has been battling cancer for some time, and is a bit of an institution in Pittsburgh.