During the year 9 ABY, Luke Skywalker was trapped on a roof connecting to the shield-barrier on Poderis, trying to escape certain capture.He was trying to find out whether Poderis was a transfer point for the Empire's new clone traffic. Luke used his heightened sensing abilities to see if Imperials were nearby; he detected blank spots in which his powers could not detect anything, which could only mean ysalamiri. He then knew it was a trap and jumped up to the roof, only to find he could not go anywhere.