Warren Haynes has been in dozens of musical scenarios since starting his career in the 1980s as a combustible guitar-slinging sideman and front person. He's been a brother within the Allmans' framework, performed with orchestras, and acted as a sessioneer to the diverse likes of Dave Matthews, John Scofield, David Allan Coe, and more. His dense and blustery Gov't Mule put him at the top of the heap of hard-jamming blues players and collaborators.

But it was playing with the Dead (once Grateful) and whatever permutations of its membership he's been a part of that has lent Haynes and his floating set lists a sense of mystery, and more than a little psychedelic soul. Having interviewed him, this writer can attest that he gives no hints as to what he and/or his raging-hot Gov't Mule will play.

On Friday, the first of two nights at the Tower Theater, the Mule kicked hard and long (two sets with an intermission) through a bunch of odd covers to go with its simmering originals. Starting with several of its newest (from 2013's Shout!) tracks like "World Boss," and the stewing, bluesy "Stoop So Low," the Mule made each simple tune into a suite, as Haynes went from languidly peaceful to aggressively choppy in under 60 seconds. During "Broke Down on the Brazos," while drummer Matt Abts made his toms rumble, bassist Jorgen Carlsson crafted a monstrous laugh of a line onto which Haynes grafted a most achingly mad solo and baby-please pleading vocals.

It was funny to find, early in the evening, that Haynes was in a mood to channel Frank Zappa, Jimi Hendrix, and David Gilmour throughout several of his own solos, as Gov't Mule eventually covered the socio-critical "Trouble Every Day" (Zappa) as a slinky funk tune, teased "3rd Stone from the Sun" (Hendrix) during several post-intermission jams, and laced its incendiary finale with Gilmour's most treacherous Pink Floyd licks for "One of these Days," and such.

With that, though Haynes was Gov't Mule's clarion-clear center - truly the eye of its hot-winded hurricane whirl - much must be said for the Mule's organ-grinding Danny Louis, a keyboardist adroit at creating a B-3 Hammond bed of jazz blues licks that would raise Philly's Charles Earland from the dead with pride and envy.