External Possession Constructions (EPCs) are prevalent across a diverse array of languages and have been analyzed as originating from several structural patterns, but Mandarin EPCs with color terms (EPCCTs) exhibit some properties that distinguish it from the other. As I propose, EPCCTs essentially result from head movement in which the possessive head moves into the verbal domain, along with which the possessor is dragged up for agreement with the possessive head. The movement of the possessive head holds unique significance. Semantically empty, it requires identification with the head it moves to for complete interpretation at Logical Form (LF). Consequently, its argument transforms into the argument of the head it migrates towards. This dynamic yields noteworthy outcomes: the possessive head assigns a theta role from each head it cyclically traverses, encompassing potential roles such as theme, agent, and affectee. Furthermore, this head movement also manifests a distinct blocking effect, wherein unstressed demonstratives blocks possessor externalization, and interestingly, what is blocked is not the possessor but the possessive head. These findings shed new light on the unique mechanics of EPCCT and contribute to a deeper understanding of relevant theories related to external possession.