A.T. Robertson Commentary Mark 15:19

"And they smote his head with a reed, and spat upon him, and bowing their knees worshipped him." — Mark 15:19 (ASV)

Worshipped him (προσεκυνουν). In mockery. Imperfect tense as are ετυπτον (smote) and ενεπτυον (did spit upon). Repeated indignities.