How to rotate the object based on the vertex of another object? Do you see the selected vertex, how do move the red circled object to the selected vertex as well as to rotate the object based on the vertex? rotation?

(This question is different from other questions as I am asking how to position the spikes based on the body's specific vertex).
Use snapping to achieve this task.

The settings of snapping:


Snap to vertex
Target - Center
Align rotation is enabled.




And move object with holding CTRL:



PS set center of the cone object in bottom of it.