Passive Spell With Hidden Icon That Calls On An Animation With Each Attack?

You know how Pulverize can call on an animation passively when the unit attacks.. well, i wanted to use this as a basis but the problem is the icon shows. Is there another spell that can call on animations with each attack but do not show the icon?

Pretty sure you can add the spell to a hidden spellbook. No icon but the spell abilities still applies to the unit.

Also, I'm pretty sure abilities like Critical Strike, Pulverize, and Bash don't exactly "call on an animation" (or do they?) They just enable the "attack slam" animation that the Blademaster, Tauren, and Mountain King have. Look at their animations and you'll see what I mean.

They do, you only see the alternate animation when they use a special strike.

I used hidden spell book + cleave ( null aoe) to play slam animation all time.

so it didn't work or did it? were you able to hide it?