I obtained this trophy by using Kinetic Grasp
next to a Reaper executing Death Blossom.
I found a list explaining how the ability works at the Overwatch Wiki on Fandom:
https://overwatch.fandom.com/wiki/Kinetic_GraspYou can absorb projectile and hitscans only, so things like Zarya's beam are a no go.
Kinetic Grasp takes 60%, of the damage coming in front of Sigma at the little ball he holds above his hand during the ability. Reaper does a max of 510 damage per enemy with Death Blossom, and 60% of that is 306. This means I had to have absorbed some other damage besides Death Blossom in the 2 seconds Kinetic Grasp was active (also because Death Blossom is 3 seconds long). Roadhog's Whole Hog does a max of 4928 damage, so it is likely the best source of damage absorption if you can activate Kinetic Grasp before getting knocked back.. You can use the link above to find the damage values of the other abilities that can be absorbed.
One final note, make sure your shield isn't blocking incoming damage while using Kinetic Grasp.