But they didn't have to panic as it was just 39-year-old fitness instructor Kenny Sia, who dressed up for his Sunday appointment in a full dinosaur costume, much to the amusement of people and medical workers at the vaccination centre in Kuching, the capital of Malaysia's Sarawak state.
Sia told Reuters he chose to wear the costume to make people laugh as well as to protect himself.
"Rather than wearing just like only face masks or face shields only, I decided to go the whole way, right? The whole suit is effectively a PPE - it's one of those overall suits," he said.
"I know the front-liners there are working day and night, vaccinating 5,000-6000 people a day, so they probably are very tired. And anything that can lift up their mood, I'll be happy to do it."
Malaysia has vaccinated about 10% of its population, faster than most of its neighbors, though the number of reported infections remain high.
The country reported 8,754 new cases on Monday, taking total infections to 844,870, the third highest in Southeast Asia after Indonesia and the Philippines.