What's this odd stuff coming out of my meringue?
Definitely egg white seepage, by the looks of the shape of it you've either over whipped the egg whites OR let them sit for too long before cooking which meant they spilt slightly before going in the oven.

Another possibility is the oven wasn't hot enough to begin with OR the environment (kitchen) was too warm. 

When ever I've cooked meringue I've had the oven on 180 for 10min then turned it off and left the meringue in undisturbed over night. Never had any issue's that way. The only time I've had seepage is when I've beaten my eggs then got disturbed by a check coming on and having to leave the whites for 5-10min before shaping and cooking...