Actually it's a character throwing a stone.

I managed to get it kind of working. I created a "remove_stone" function that makes it passable/invisible/ent_remove. I also made the alpha fade out after a certain amount of time and if the alpha reached "0" , just call the remove function again. It's all really messy actually...

Is there a way to make the stone ignore the character that's throwing it?

I can show you my code if you think that would help. I would like to make it look a little bit more realistic.