Is that true that this Universe like a horn?

Scientist have made some maps of the Universe but the further they see into the depths of Universe the further the Universe seems to be extending. It seems they are no where near to finding the frontiers of the Universe. Same is the case on micro scale, they keep on finding ever smaller particles. So, could be still some time, till shape of the Universe can be known.

However, not sure if all trumpets are of the same basic shape, or what could be the shape of God's trumpet?

As a sound of a bell is usually used to indicate end of a class or school, Similarly the mention of trumpet could be referring to a sound to indicate end of times.