Shimadoros appears as a dog-like Spectrobe. Like its previous forms, it also has a large structure covering its entire back. On top of this structure is a pair of horns, with a spike on top between. It also has a pair of cannons on its side, underneath the covering.
Shimadoros' name is a combination of two parts: the "shima" part is the same corruption of "shiba" (柴) brought forward from its Child form, whereas "doros" is a styling of the Japanese onomatopoeia どろどろ (dorodoro), which represents the pealing of drums and thunder. This relation is further strengthened in Origins, where every voice it makes is accompanied with background sounds of the taiko (太鼓, drum) and kane (鐘, chime).
Shimadoros' character design is inspired by the Kishiwada Danjiri festival (岸和田だんじり祭), where young men drag around a 4-ton mikoshi shrine through the streets of Kishiwada, Osaka at high speeds. This explains the tomoe designs on its sides and the generally bulky body shape.
Shimadoros is the second of three Spectrobes confirmed to be derived from Kansai culture, the other two being Boma-Boma and Komadoros.