The Royal Rumble is the one WWE show where there are more surprises guaranteed for fans than any other.
With the men's and women's Rumble matches a breeding ground for shocks and twists, it means the odds of a returning star showing up are probably higher than at any other point in the year.
With a number of big names absent from television for so long, there's also added expectation that some legends of the business could be in line for an appearance on Sunday.
But what are the chances of The Undertaker, John Cena and Ronda Rousey's music hitting once the Rumble matches are underway? Let's take a look.
The Undertaker hasn't wrestled inside a WWE ring since July, when he teamed with Roman Reigns to defeat Drew McIntyre and Shane McMahon at Extreme Rules.
Such a lengthy absence could point to a return sooner rather than later, but the Royal Rumble doesn't quite feel like the right place for that to happen.
For starters, The Deadman has only appeared in one actual Rumble match, in 2017. He only wrestled at the Rumble on one other occasion, in 2010, when he defeated Rey Mysterio with the World Heavyweight Championship on the line.
The Undertaker's WrestleMania feuds have traditionally begun after the Rumble, a show in which the full-time roster usually has more of a say in what is happening as opposed to the part-time competitors.
With that in mind, it's probably wise to back against a surprise appearance from the veteran this Sunday.
It seems highly unlikely Brock Lesnar is going to enter the Royal Rumble with the WWE Championship and go on to win the match.
As such, there's bound to be a surprise somewhere, and perhaps even a shock return who will eliminate The Beast Incarnate, win the Rumble and set up a match for the title at WrestleMania 36.
Don't bet against that man being Cena.
His in-ring career looks to be winding down, but he's almost certainly got one more big run in him. That could come this year, against a man he's faced on multiple occasions.
Cena vs. Lesnar has occurred several times in the past, most notably when The Beast returned to the company in 2012.
Sure, Cena has plenty going on away from WWE which could disrupt an in-ring return on the road to WrestleMania, but the lure of a big match may be too hard to resist for the 42-year-old.
Throw in the potential of Cena eclipsing Ric Flair's all-time record for world titles, and you have all the ingredients for a fascinating WrestleMania feud.
With only four women confirmed for the Royal Rumble this Sunday at the time of writing, there's bound to be some big surprises.
Could one of those be Ronda Rousey? Perhaps.
She hasn't been seen in WWE since her defeat at WrestleMania 35 last year. The company never made any guarantees about her returning in the future, and there's been little in the way of leaks regarding a potential return.
But if WWE was to pull the trigger on a return for the former UFC star, this weekend would be perfect for various reasons.
The women's Rumble has had little in the way of enticing build and promotion, and dropping a star name like Rousey in as a huge twist would grab some headlines.
Also, the prospect of her avenging her defeat to Becky Lynch at The Show of Shows last year makes a return possible, too. That was Rousey's one and only loss in WWE, and the storyline for a rematch would write itself if she won the Rumble and The Man defeated Asuka on the same night.
Out of all the possible returns, this is by far the most appealing and likely.