What is a parasite that looks like a flea but feeds like a tick.?

The parasite you are referring to is likely the "chigger," specifically the larval stage of certain mites in the Trombiculidae family. Chiggers have a flea-like appearance but feed on the skin of their hosts in a manner similar to ticks. They attach themselves to the skin, inject enzymes to digest tissue, and then consume the resulting fluid, leading to intense itching and irritation.