In Heir to the Empire, Thrawn puts the Force-deflecting abilities of ysalamiri creatures to use when he attempts to form an alliance with the Dark Jedi Jorus C'baoth.
With that in mind, it's a good thing Thrawn sat out Jedi Knight: Mysteries of the Sith (PC, 1998), which tasked players specifically to "Kill the Fool With the Ysalamiri." This multiplayer mode plays something like a "King of the Hill"/"Oddball" style, the difference being that within a 10-meter radius of said fool, no Force powers can be used, changing up the game's core action considerably. Meanwhile, in single-player mode, ysalamiri "were usually hanging out in a place that would frustrate you for not being able to use your Force powers," recalls Stephen Shaw, the project leader on the game.
Apparently happy with appearing in expansion packs, ysalamiri would later be available to players craving their own Thrawn-like, Force-deflecting tactics in Petroglyph's Empire at War: Forces of Corruption (PC, 2006).