Steve Hornsby from Bournemouth said the 3cm diameter balls came raining down late on Thursday afternoon during a hail storm.
He found about a dozen of the balls in his garden. He said: "[They're] difficult to pick up, I had to get a spoon and flick them into a jam jar."
The Met Office said the jelly-like substance was "not meteorological".
Mr Hornsby, a former aircraft engineer, said: "The sky went a really dark yellow colour.
"As I walked outside to go to the garage there was an instant hail storm for a few seconds and I thought, 'what's that in the grass'?"
Walking around his garden he found many more blue spheres were scattered across the grass.
He said: "The have an exterior shell with a softer inner but have no smell, aren't sticky and do not melt."
Mr Hornsby said he was keeping the balls in his fridge while he tried to find out what they were.
Josie Pegg, an applied science research assistant at Bournemouth University, speculated that the apparently strange phenomena might be "marine invertebrate eggs".
"These have been implicated in previous 'strange goo' incidents," she said. "I'd have thought it's a little early for spawning but I suppose we've had a very mild winter.
"The transmission of eggs on birds' feet is well documented and I guess if a bird was caught out in a storm this could be the cause."