Sprite/spawner smears

A sprite set up to spawn rocks doesn't spit out complete rocks but it creates a growing smear as they move.

Are you spawning every tick?

"Every tick" is a condition, basically every frame, if you don't have other conditions to control it, like "Every x seconds".

Otherwise it is difficult to help without seeing how you've set it up.

Thanks for your concern! You are a kind person. I'm trying to help my 9 year grandson learn how to build the Space Shooter game. The tutorial we're following on youtube by RedFoc is actually done with Construct 2 but so far everything is working. A single sprite is set up to spawn rocks every two seconds. That works. Then the tutorial says to "clone" more sprites and then set up a random spawner instance. If you clone you get spawner 1,spawner 2 etc. The random instance seems to recognize only the original word spawner. We tried cut and paste to make every sprite have the name spawner. That works as far as spawning from each sprite every two seconds but won't allow a random instance to be set up(as far as we know). The question seems to be: what is the action that accompanies SYSTEM PICK A RANDOM SPAWNER INSTANCE?

Red Foc simply moved the action SPAWN ROCK on LAYER 0 down from the previous event which was SYSTEM EVERY 2 SECONDS.

I'm not familiar with the tutorial you are referring to, but the way to pick a random sprite object from multiple sprite objects is to put them together in a "family" (only available in the paid version of C3 I believe).

Otherwise, you don't need to use clone to make multiple spawner object copies at all. Just use a single spawner sprite object, and drag multiple copies (instances) onto your layout. Then you can use the "System-Pick random instance" condition on that single spawner sprite object.