Based on the Japanese-American Shigeki Miyake-Stoner. Shigarific related to Asianism (Japanese in particular), or other things related to Shigeki, such as roleplaying or quotes that he excessively uses like "weak sauce".
A combination of "shit" and "terrific" used as an adjective to describe something something particularly bad, in a mildly sarcastic tone. Usually in response to a question of quality.