Ysalamiri are furry, lizard-like tree-dwellers (on average, about 50cm/1.6ft in length) from Myrkr, most known for its ability to repel the Force by creating a Force-neutral bubble. This ability evolved in response to predation by the Force-sensitive vornskrs. Several ysalamiri together can expand their Force-neutral bubble by exponential distance - sometimes miles.
Adult ysalamiri grow up to 90 or 120 centimeters and hatch their young from bubble-like eggs. Ysalamiri sink their claws into the olbio trees on which they live and draw nutrients. It was very difficult to remove a ysalamir from its tree without killing it, although Talon Karrde's smugglers found a way, enabling Grand Admiral Thrawn to do it as well. Thrawn used ysalamiri for defense by attaching them to a back harness which allowed Grand Admiral Thrawn and his men to remain safely inside the ysalamiri's force repelling bubble. He used this trick to gain the attention of cloned Dark Jedi Master Joruus C'baoth and accelerating the Spaarti cloning process without the usual side-effects (which occurred when similar Force imprints interfered with one another).
Ysalamiri do not actually negate the Force; since all existence was infused with Force energy this would not be possible. Rather, they projected a Force bubble inside which it is completely neutral and unable to exert any influence. A single bubble measures up to 10 meters in diameter; groups of ysalamiri can extend this radius by miles, depending on how large the group was.
Former Imperial Grand Admiral Demetrius Zaarin used ysalamiri placed into the cargo hold of Emperor Palpatine's Star Destroyer, Majestic, as part of his plot to assassinate Palpatine and take his place in a coup.
Miriskin is a commodity supposedly made from ysalamir skin.