The Peacock network opened its 2026 upfront presentation to advertisers Monday at Radio City MusicaHall with a laser light show that included all the colors of NBC ‘s logo rainbow, followed by a monologue and musical number from “Las Culturistas” hosts Bowen Yang and Matt Rogers. Set to the tune of Bruno Mars and Rosé’s “APT,” Rogers and Yang sang about the virtue of “Ads on NBC, ads on NBC,” while surrounded by dancers sporting peacock feathers in front of a big pink background cover in NBCUniversal and Comcast signage. When Rogers and “Saturday Night Live” vet Yang exited the stage, a digital short starring NBCU ad chief Mark Marshall began to roll. In the clip, Marshall is going to get a new tattoo to show his love for NBC on its upcoming 100th birthday. And while he doesn’t have much space left — he’s devoted most of his body to the logos of NBC advertisers — he’s saved the spot right by his heart for NBC.…