A teenage boy mopping the floors at a fast food outlet in Caboolture last night sustained a deep laceration to his hand during an armed robbery by a man wearing a spiderman mask.

Around 8.30pm a man carrying a knife entered the Lear Jet Drive business and approached a 15-year-old employee. The man spoke to the boy briefly before lunging at him and striking him once in the hand with the knife.

The man then approached the counter, threatened a second employee and demanded cash.

He fled on foot with a sum of cash, and may have then entered a vehicle.

The Caboolture boy was transported to CabooltureHospital for medical treatment.

The man is described as Caucasia n, approximately 180cms tall with a proportionate build and was wearing black knee length shorts, a navy hooded jumper, white sandshoes and a full faced red and blue spiderman mask.