2 When the day of Pentecost came, they were all together in one place. 2 Suddenly a sound like the blowing of a violent wind came from heaven and filled the whole house where they were sitting. 3 They saw what seemed to be tongues of fire that separated and came to rest on each of them. 4 All of them were filled with the Holy Spirit and began to speak in other tongues as the Spirit enabled them.
...reports the descent of the holy spirit on the 11/12 disciples of Jesus but the original pentecost was relative to the 12 disciples of John the Baptist:
19 While Apollos was at Corinth, Paul took the road through the interior and arrived at Ephesus. There he found some disciples 2 and asked them, “Did you receive the Holy Spirit when[a] you believed?”
They answered, “No, we have not even heard that there is a Holy Spirit.”
3 So Paul asked, “Then what baptism did you receive?”
“John’s baptism,” they replied.
4 Paul said, “John’s baptism was a baptism of repentance. He told the people to believe in the one coming after him, that is, in Jesus.” 5 On hearing this, they were baptized in the name of the Lord Jesus. 6 When Paul placed his hands on them, the Holy Spirit came on them, and they spoke in tongues and prophesied. 7 There were about twelve men in all.
A conspiracy and an usurpation and a co-optation are in action here.