A wellbore isolation device comprises: a substance, wherein the substance: (A) is a plastic; and (B) undergoes a phase transition at a phase transition temperature, wherein the temperature surrounding the wellbore isolation device is increased or allowed to increase to a temperature that is greater than or equal to the phase transition temperature. A method of removing a wellbore isolation device comprises: causing or allowing the temperature surrounding the wellbore isolation device to increase; and allowing at least a portion of the substance to undergo the phase transformation. A method of inhibiting or preventing fluid flow in a wellbore comprises: decreasing the temperature of at least a portion of the wellbore; positioning the wellbore isolation device in the at least a portion of the wellbore; and causing or allowing the temperature surrounding the wellbore isolation device to increase.