You are difficult to move or knock down.
Prerequisite(s): Con 15.
Benefit(s): Once per combat when an attack or effect would knock you prone, you can ignore that effect as a reaction. In addition, the distance that any nonmagical effect that would move you against your will is reduced by 5 feet.
Starfinder Character Operations Manual © 2019, Paizo Inc.; Authors: Alexander Augunas, Kate Baker, Simone Dietzler, Jennifer Dworschack-Kinter, Leo Glass, Sasha Lindley Hall, Amanda Hamon, Vanessa Hoskins, Jenny Jarzabski, Jason Keeley, Lyz Liddell, Luis Loza, Ron Lundeen, Crystal Malarsky, Robert G. McCreary, Conor J. Owens, Joe Pasini, Owen K.C. Stephens, Jason Tondro, and Landon Winkler.