Yo Gabba Gabba: Character Beaned Me With Bottle ... Claims Father

"Yo Gabba Gabba" allegedly delivered a special message to one father when they humiliated him in front of his kids and then nailed him in the head with a water bottle ... so says the very angry dad.

According to an email sent to organizers at the "We Are LA Family Music Festival," Todd Elliott claims he took his daughters to the StubHub Center in Carson, CA Saturday for the charity event, when they found themselves backstage searching for a bathroom.

Todd says the staff gave him wrong directions ... and he ended up in an elevator with the cast of Yo Gabba Gabba and two handlers as they were headed to the stage to perform.

Todd claims he tried getting off the elevator with his daughters, but the characters and staff refused to make room. The situation escalated and Todd claims one of the characters hurled a water bottle at the back of his head in front of witnesses, including his daughters.

It's unclear if the alleged culprit was Muna, Foofa, Brobee, Toodee, Plex, or DJ Lance Rocks.

We're told Todd did not file a police report ... but he wants an apology from all involved.

We reached out to Yo Gabba Gabba ... so far no word back.