Laravel 5 - What is wrong with this filter?

I want this Route

Route::get('/{var?}',['uses'=>'indexController@wrongCredentials', 'as'=>'wrongCred'])->where('var', '[wrongCredentials]+');

Send to the indexController@wrongCredentials only and just only the URL:http://ift.tt/2auu4QL.

It is not working.

If I type /rat, /wo, /wrongCredentials, and others strings the code sends me to the controller.

If I type /bat, cat/ and others don't.

I've already tried others combinations like:

Route::get('/{var?}',['uses'=>'indexController@wrongCredentials', 'as'=>'wrongCred'])->where('var', '[^wrongCredentials$]+');

Route::get('/{var?}',['uses'=>'indexController@wrongCredentials', 'as'=>'wrongCred'])->where('var', '[/^wrongCredentials$/]+');


Route::get('/{var?}',['uses'=>'indexController@wrongCredentials', 'as'=>'wrongCred'])->where('var', '/^[wrongCredentials]$/+');

But none of them worked properly.

Can someone tell what am I missing?

via Chebli Mohamed