Srimad Bhagavatam Canto 10, Chapter 74, Text 45

SB 10.74.45

caidya-dehotthitam jyotir
 vasudevam upavisat
pasyatam sarva-bhutanam
 ulkeva bhuvi khac cyuta
 
Translation: 
 
An effulgent light rose from Sisupala’s body and, as everyone watched, entered Lord Krsna just like a meteor falling from the sky to the earth.
 
Purport: 
 
In this connection, the acaryas remind us that Sisupala is actually one of the Lord’s eternal associates playing the part of a belligerent demon. Thus to most observers it appeared that Sisupala achieved the impersonal liberation of merging into Lord Krsna’s bodily effulgence. In fact, after being liberated from his mortal frame, Sisupala returned to the side of his master, the Supreme Lord of the spiritual world. The following verse further explains this.
Srimad Bhagavatam Canto 10, Chapter 74, Text 44
Srimad Bhagavatam Canto 10, Chapter 74, Text 46