I bet that thing made you back up and gasp in fear. This is an 'oops' egg commonly seen in pullets who are still working out the kinks in the egg making factory. Let me tell you those young gals can come up with some doozies that will make Stephen King drool in envy. Don't worry, your hen should be okay. However if you continue to see this type of egg you will need to be concerned. Occasionally an older hen will produce something like this and may indicate an issue going on internally , But in a young, healthy pullet just starting out, I think you are in the clear.
Honestly, I'd preserve this egg in a jar and put it on display at Halloween.