This paper describes surface plasmon polariton (SPP) modes that show extraordinary propagation behaviors along metal stripes with finite width, including multiple energy condensations. Phenomenological and quantitative investigations are carried out on these behaviors. Images of SPP modes at output edges for wide stripes exhibit multiple spots that spanned the lateral side of the stripes. The spot number is monotonously decreased as the stripe length increases. Besides, the input versus output power ratio shows a stepwise change as changing the propagation distance. We present a model of SPP modes to explain these behaviors.