Abstract: A mold core for producing a component of fiber composite material with a cavity. The mold core makes a particularly simple and efficient demolding process possible by a mold core extending along a longitudinal axis and which is in the form of a hybrid core and which includes, viewed in a cross section perpendicular to the longitudinal axis, a first core portion and a second core portion, wherein the first core portion is formed from a first material with high stiffness and low coefficient of thermal expansion, and wherein the second core portion is formed from a second material that differs from the first material, and is configured such that, under predetermined conditions, its form changes in a predetermined manner such that removal of the mold core from a cavity in the cured component is made easier.