The guardian beam is not rendered if the attacked entity has the entity id 0. Guardians directly write the entity ID in an integer metadata field, and assume 0 means no target (unlike fireworks, which use an OptionalInt (
MC-111480) to prevent this).
Since entity IDs start at 1 after 19w05a, this is unlikely to cause problems in practice, but it is still weird that one entity uses OptionalInt and the other doesn't.
- discovered while testing
MC-85177 Guardian beam is not rendered if targeted entity is the first entity in the world