Ice Spice Flaunts Her Ass in Sheer Dress at 'SpongeBob' Movie Premiere

"The SpongeBob Movie: Search for SquarePants" became ground zero for panicked parents testing their cover-your-kids'-eyes reflexes ... 'cause Ice Spice rolled in to the family-friendly affair practically naked!

The rapper -- who has a role in the flick and contributed the original song "Big Guy" -- went shockingly bold at the NYC premiere for the PG-rated movie Wednesday, rocking a sheer lace getup that left little to the imagination, flashing her thong and plenty of bare cheek.

Ice was posing up a storm in front of that bright, bubbly SpongeBob backdrop ... a wild juxtaposition, considering this was a kids’ movie premiere with families everywhere.

Maybe she missed the fashion memo -- or maybe she nailed it, dressing like that so she could ditch the extras and dive straight into the sea after the premiere to hunt down SpongeBob and his SquarePants herself.

Of course, parents weren’t thrilled -- Paramount plugged a pic of Ice from the premiere, and the comments immediately went up in flames, with people questioning how she was allowed at a kids’ movie looking like that.