Original title was ポルターガイスト or porutaagaisuto. So, clearly a loanword from German! Furinkan notes that: "
In German, "poltergeist" means "loud ghost". They are known a ghosts that clatter, bang or smash objects."

May 25th, 2011. Author's note:
"Q: Do you believe you can jinx yourself?
A: When the staff and I were drawing during the Hanshin game they seemed to lose more often."