What does this borderline ki first Krilin and now Goku get mean? In Dragon Ball Super episode 76 Krilin had an aura ki we never seen before, it was drawed surrounding very closely his body:





Now in the preview of Dragon Ball Super episode 98 we see Goku has the same aura:





What does this borderline ki first Krilin and now Goku get mean? It's the only 2 times we've seen this kind of aura in the entire Dragon Ball universe.
We got an answer to this question in the last episode(98). Basically its just a barrier that is used to protect them against posion, so it cannot make contact with their skin. 
From this we can conclude that it had nothing to do with the aura Krilin has showed us in a previous episode.