If you right click a spawner with a Wolf or Ocelot egg, it will crash the client. When you log back in the world or server, it either crashes the client (Server), or changes the spawner to its latest change before the crash, or pig for default (Singleplayer).
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Comments 5
wolf fixed for next version (ocelot probobly too) MC-87759
attach the crash report as file, not as image (minecraft/crash-reports/crash-<DATE>-client.txt)