The latest I can find on Bad Spaniels is that the courts concluded they did not infringe the trademark exactly because it was an obvious parody, but that it tarnished the brand because of the association with dog feces[0]. Notably, it seems that brand confusion is still central to the infringement question, and SCOTUS ruled that parody plays into that.

> Reaching the Supreme Court, the case took another turn in 2023 when the Court vacated the Ninth Circuit’s decision, unanimously ruling that the Rogers test does not apply in cases when a trademark is used as a source identifier, rather than as a purely artistic work. As a result, the Supreme Court remanded the case for the district court to reconsider Jack Daniel’s counterclaims under traditional trademark principles.

In the food truck case, clearly they are using it as their own brand identifier (so it's analogous to Bad Spaniels), and clearly it is a parody, so clearly it is not trademark infringement as with BS. Unlike the BS case, they're also not tarnishing the Eggo brand, but just making a playful pun, so that outcome doesn't seem likely here.

[0] https://www.internetandtechnologylaw.com/bad-spaniels-iii-pa...