Spawn at x y+2 z with yaw: Direction in yaw in deg. relative to S of event/target entity, pitch: head pitch of event/target entity in degrees, vx: sin (DEG to RAD (direction in yaw in deg. relative to S of event/target entity+180)), vy: head pitch of event/target entity in degrees*-0.05, vz: cos (DEG to RAD (direction in yaw in deg. relative to S of event/target entity))
In "on entity tick update" do this:
If pick random 0 to 1 < 0.01:
Spawn at x y+2 z with yaw: Direction in yaw in deg. relative to S of event/target entity, pitch: head pitch of event/target entity in degrees, vx: sin (DEG to RAD (direction in yaw in deg. relative to S of event/target entity+180)), vy: head pitch of event/target entity in degrees*-0.05, vz: cos (DEG to RAD (direction in yaw in deg. relative to S of event/target entity))