A.T. Robertson Commentary Mark 1:26

"And the unclean spirit, tearing him and crying with a loud voice, came out of him." — Mark 1:26 (ASV)

Tearing him (σπαραξαν αυτον). Margin,

convulsing him like a spasm. Medical writers use the word for the rotating of the stomach. Luke 4:35 adds "when the demon had thrown him down in the midst." Mark mentions the "loud voice" (φονη μεγαλη), a screech, in fact. It was a moment of intense excitement.