Octomom -- Some A-hole EGGED My House

Octomom got a nice little house-warming gift this weekend -- when her brand new pad was PELTED WITH 3 DOZEN EGGS ... by some mystery vandals.

Sources close to Octo tell TMZ ... the mom of 14 wasn't home when the prank went down late Friday night -- she was in NYC attending a drag queen show at XL nightclub -- but her children were.

We're told Octo discovered the mess outside her Palmdale house when she came back Saturday morning -- with eggs covering her van, garage door and front drive-way.

Not only that ... we're told the eggs sat for so long, they attracted a ferocious army of ants, which fed off the rotting goo.

As for the damage ... we're told it cost Octo $100 to clean the eggs, and another $100 to kill the ant infestation.