Once they thought that I am a hoax. I am venomous and I can detect electric fields. What am I?
This could be a
Scientists first thought recovered remains of a platypus was different creatures fused together. They thought it was a hoax.
They have a spur in their hind foot which releases venom into its victim
Uses elecrolocation to find its prey
This answer was given by someone else but was deleted due to inadequate (zero) reasoning for proving their answer.
I think you are
Trump's speech: https://www.politico.com/news/2020/02/28/trump-south-carolina-rally-coronavirus-118269
Venomous: Yeah Corona virus is really venomous!
Detect electric fields: Corona discharge https://en.wikipedia.org/wiki/Corona_discharge