A substitute foot with two accents is a spondee.
First of all, a substitute foot is a metrical foot, that is to say the basic rhythmic unit that is found in a line of verse in poetry. There are different types of feet, such as the iamb, the trochee, the anapest, the dactyl and the spondee; however, the spondee is the only one that consists of two stressed syllables. In other words, the spondee is the only one that includes two accented syllables: syllables that are pronounced louder, longer, and generally at a higher pitch than the rest of the syllables.
