Target Was Set

public event Action<Unit> TargetWasSet

This event fired when the shell’s target is set or changed (via Setup or SetTarget). Passes the new target Unit.

// this example code can be run from anywhere you have a ShellService reference injected

var shell = shellService.SpawnShell(shellPrefab, shootPoint.position, shootPoint.rotation, ownerUnit, targetUnit);
shell.TargetWasSet += OnShellTargetWasSet;

void OnShellTargetWasSet(Unit target)
{
  // your actions here
}