Consider the lore related to gargoyles. Their design and construction has a specific purpose: to ward away evil spirits.
That being the case, go ahead and describe that gargoyle as hideously as possible. Then, when the PCs preemptively smash it, have a nasty wraith or shadow jump out of the wall and attack them from behind.
If they still don't get the hint, do it to them the next time, too. And so on.
Then, one day, long after they've decided to let the gargoyles do their jobs in peace, you can have one attack the PCs. In revenge for all of the fallen gargoyles that have gone before.