I’m not suggesting that Mystic Dead, the local rock band intensely devoted to replicating the music and tie-dye nuances of the Grateful Dead, is a creepingly ubiquitous entity.

It IS true, though, that if, somehow, principal deceased members of the original Dead – Jerry Garcia, Pigpen, Brent Mydland and Keith Godchaux – came back to life and the band was suddenly at full strength, they’d be opening for Mystic Dead and not the other way around!

This is one way of explaining why Mystic Dead are headlining both Friday and Saturday at the popular Mystic River Jam taking place at the Mystic Shipyard. But, beyond Dead-ness, there’s a lot of great music across a variety of styles – and plenty of food, beverage and merch to enhance the fun.

The full lineup:

Friday: The Pneumatics (4 p.m.), The Troublemakers (5 p.m.), Wooly Mammoth (6 p.m.), Mystic Dead (8-10 p.m.).

Saturday: The Subliminals (1 p.m.), The Decker Bandits (2:15 p.m.), Jeremiah Hazed (3:30 p.m.), Glaucoma Suspect (4:45 p.m.), Oblivious Fools (6:15 p.m.), Mystic Dead (8-10 p.m.).

Mystic River Jam, 3-10 p.m. Fri. and noon-10 p.m. Sat., Mystic Shipyard, 100 Essex St. Mystic; $30 Fri., $40 Sat., $60 weekend; mysticriver.jam.com