I found this on my garage floor a day after a mechanic worked on my 2008 ES350. Actually, he just removed the air filter housing assembly to have access to wire harness chewed by rats deep in the engine bay. I just want to be sure if this is really part of the assembly (and exactly where) so I can call back the mechanic to put it back.

 

If everything is still working, you probably don't need it.

 

Don't worry. Your Lexus is just shedding. Cars do that sometimes.

 

The item pictured looks like a rubber foot from a small appliance or tool; perhaps it fell off something else in your garage? It doesn't look like anything I've seen used on a Toyota/Lexus product.