Often a great dove is drawn in the pictures of children's bible stories when Jesus got baptised. Because of this people often associate spooky doves with the Holy Spirit.

The bible's version:

And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him; and behold, a voice from heaven said,

“This is My beloved Son***, with whom I am well pleased.”

-- Matthew 3:16-17 (ESV); Luke 3:21; John 1:51

And at Jesus transfiguration God also announced:

And a cloud overshadowed them, and a voice came out of the cloud, “This is my beloved Son; listen to him.” -- Mark 9:7 (ESV)

According to Gemini:

Doves descend by using a scooping wingbeat that creates lift and glides, allowing for a smooth descent. Air sacs throughout their body act like tiny airbags, keeping them light and maneuverable as they flutter down. This unique combo makes a dove's descent slow, graceful, and unlike any other bird.

According to Mark, they saw a cloud overshadowing them at that moment. To Matthew, Luke and John it appeared like a descending dove. They most likely did not see an actual "dove", because nobody say anything about what happened to the "dove" after it rested on Jesus?

I think it was probably a cloud that gracefully descended onto Jesus, while they experienced the presence of the Spirit of God and even heard God's voice. The graceful descent of the cloud was only compared with the graceful descent of a dove.