Another one is to play about monster that looks similar, but are hated enemies, like mistaking a githyanki for a githzerai.
It can lead to "nice" things like prising the legend of Zerthimon to a 'yanki.
Or telling things like "These are svirfneblin, deep gnomes. And since you know that drows ("deep elves") are utterly evil, duergars ("deep dwarves") are utterly evil, even those "deep gnomes" must be utterly evil!"
A very amusing one imho is the "reverse thing", like telling that a normal chest is actually a mimic, or that a statue is a gargoyle or a stone golem. It could be like "Eric and the Gazebo 2.0".