Steve Hutchings' injury-time penalty and substitute James Franklyn's 94th-minute leveller ensured an incredible ending as it finished 2-2.
Horndean were cruising to victory and on course to go five points clear at the Wessex Premier summit with earlier efforts from Connor Duffin - playing in a protective face mask after breaking his nose in the weekend win over Bashley - and Zak Willett.
But Moneys kept battling until the end and got their rewards with two stoppage-time goals to pick up what had appeared the unlikeliest of points.
The Deans' leading scorer Duffin was a surprise name on the team-sheet after manager Michael Birmingham had revealed at the weekend he could be without him for the rest of the season following his nasty facial injury.
But Duffin was back out on the pitch four days after the incident and his curling free-kick gave Horndean the lead on 11 minutes.
When Willett rifled home his 28th goal of the season 10 minutes after the restart - moving him just one behind club leading marksman Duffin - the visitors were on track to move five points clear of second-placed Baffins Milton Rovers.
Things appeared to be going from bad to worse for Moneys with Hutchings sent to the sin-bin for dissent on 69 minutes and boss Glenn Turnbull receiving a red card soon after.
But they had a lifeline when Hutchings returned to the field, won and converted a penalty on 93 minutes.
Surely Moneys could not do the unthinkable, though, yet just a minute later Franklyn rounded Cameron Scott and slotted home to snatch a dramatic point to leave table-toppers Horndean on their knees.