Former Coronation Street star Ryan, who plays Rafael Humphries in the Channel 5 soap, was seen lurking around Toadie’s (played by Ryan Moloney) nineties themed birthday party.
However, he chose not to enjoy the celebration but instead stole a key card to a room and went through his neighbours belongings.
The mysterious character was also seen getting emotional when he came across a chess piece during his search.
Another eerie scene saw Rafael standing over Paul Robinson (Stefan Dennis) as he slept.
Yet the most shocking moment came when he removed his shirt to reveal a back covered in horrific scars.
Ryan did not utter a single word for his debut in the Neighbours’ late night special – entitled Hit And Run.
But that didn’t stop the viewers from speculating what he may bring to the long-running soap.
Some believe Rafael could be another one of Paul’s secret children, with one writing: “Don’t tell me Jason Grimshaw is another long lost son of peg leg Paul Robinson!”
Another asked: “Who is this mystery man skulking around? Surely Paul doesn’t have another long lost son.”
“Neighbours is getting far-fetched now,” stated a third. “Don’t tell me Jason Grimshaw is another one of Paul’s kids!”
Others likened Ryan’s Coronation Street character Jason Grimshaw to Weatherfield serial killer Pat Phelan (Connor McIntyre).
One said: “Jason Grimshaw creepily standing over Paul Robinson’s bed, he really did spend too much time with Pat Phelan before he left Weatherfield!”
Ryan recently revealed to press including Express.co.uk, that his exit from the soap will be “quite sad”.
He said: “By the end of it, people are going to find out whether Rafael is a good guy or a bad guy.
“I was going to tell you which then, but I won’t because you might as well find out as it goes along. You’ll want to go on that journey with Rafael.
“For Rafael’s character, you’ll see a mixed bag of emotions of what he is and who he is and then you can make your own decision.”
Neighbours airs tonight on Channel 5 at 5.30pm.