SPOILER WARNING: This article contains major spoilers for "Crisis on Infinite Earths, Part 2," the second installment of this year's Arrowverse crossover.
A long-missing Arrowverse character made their return on Chapter 2 of The CW's "Crisis on Infinite Earths."
As the assembled heroes mourned the death of Oliver Queen, The Monitor appeared with Harbinger. They have need of Ray Palmer's laboratory on the Waverider, but Sara has promised her team that they won't be involved in another crossover event. Since Earth-1's Waverider is off-limits, they decide to borrow a Waverider from Earth-74. Once Harbinger arrives on Earth-74, the only person she finds on the Waverider is Heat Wave, and the new voice replacing Gideon: Wentworth Miller's Leonard Snart.
Miller starred as Snart/Captain Cold on Seasons 1-4 of The Flash, before moving over to DC's Legends of Tomorrow for Season2 1-3.
"Crisis on Infinite Earths" continues in The Flash on Tuesday, Dec. 10 at 8 p.m. ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, Jan. 14 in Arrow at 8 p.m. ET/PT and in DC's Legends of Tomorrow at 9 p.m. ET/PT.