Huge Lawnmower Problem?

Sounds like your mower locked up...remove the plug flip it over try to move the blade.if u can't get it to move it might be locked up...if u break it free flip it back over, install the plug, check the oil and start that sucker.its probably gonna smoke like hell because u got oil in the muffler.....the only other thing it might be is the sheer pin....if u hit something with the mower the shear pin will break saving the motor but will throw it outta time......just guessing with what info u have given...