This is a simple test / example of crashing processes by asking a peer to over-fill their channel message queues. It works by repeatedly sending Directory.ReadDirents calls to the server backing /svc (generally Component Manager) without ever reading replies. The peer has no way of knowing that their replies aren't being read and then are killed by the kernel to avoid consuming too much kernel memory.
Run this by adding //src/tests/fidl/syscalls/crasher to the build and running:
ffx component run --recreate /core/ffx-laboratory:crasher 'fuchsia-pkg://fuchsia.com/crasher#meta/crasher.cm'