Swampie A Swampie ( PROSE : " Doctor Who and the Power of Kroll " ) was a green - skinned humanoid from the planet Delta Magna . When human s colonised the planet , they forced the Swampies to move offworld to Delta III , a moon . Without proper technology , the Swampies became primitives , operating as a tribe and performing sacrifices . Their technology was also very basic and so they relied on their environment during conflict . Biology . Swampies were humanoid is shape but their skin was green in colour . Their hair was always braided and it was also green . As they could not rely on advanced technology , the Swampies were usually agile . ( TV : " The Power of Kroll " ) Society . Swampies were greatly opposed to the presence of humans on Delta III . They intended to overthrow them by force and knew them as the " dry - foots " . The Swampies worshipped Kroll as a god and relied upon him to defeat their enemies . They performed dances of worship to praise him and offered sacrifice s to appease him . Their methods of sacrifice varied greatly as dictated by the Seven Holy Rituals . One such method involved an individual pretending to be Kroll by dressing up . Another involved the use of vine s tied around the sacrifice . The vines would constrict in the sunlight becoming tighter until the victim ' s back was broken . Swampies operated as a tribe with an appointed head who was also the religious leader . They were literate and had a large book that recounted their history . Because of their simple lifestyle , the humans considered them to be dumb and foolish . Ranquin was aware of such opinions and objected to them . ( TV : " The Power of Kroll " ) Technology . The Swampies had a low level of technology , which meant they were easily evicted by the human s . They generally used spears and lived in grass huts . They made use of their environment , such as using vines to kill people in sacrifice . They were incapable of effectively using firearm s as they had never encountered such weapons . ( TV : " The Power of Kroll " ) History . Colonisation of Delta III . The Swampies were originally native to Delta Magna , but were moved to Delta III , one of the planet ' s moon s by human colonists , who they referred to as " dry foots " . They had human allies in the group , Sons of Earth . However the Sons ' form of support proved ineffective . They predicted this with their sacred relic , actually the fifth segment of the Key to Time , and accepted this movement . Worship of Kroll . The colonists also transplanted several giant squid to the moon for the Swampies to hunt . One of these ate the sacred relic and mutated into the " god " , Kroll . When the humans discovered that methane could be gathered on the moon they set up a refinery to gather it . They also gathered protein that was sent to Delta Magna . This angered the Swampies , who turned to a religious leader , Ranquin . They were supplied with guns by Rohm - Dutt . They praised Kroll at night , intending to attack the dry foots the next day . They encountered a patrol in the swamp and fired . The guns misfired and Kroll appeared and attacked them . They realised that Rohm - Dutt was working for the refinery , and they took him prisoner . They also captured the Fourth Doctor and Romana . They devised an elaborate execution for them but they escaped . They pursued them but Kroll attacked them . This shook their belief in Kroll as their god . The Swampies attacked the refinery as did Kroll . Kroll killed Ranquin and the Doctor restored the beast to his normal size . The refinery was closed and the Swampies freed from its oppression . ( TV : " The Power of Kroll " )