Both Finster and Zordon refer to the Terror Toad as "a" Terror Toad, indicating that there may be more than one member of the monster's species.
Trini and Zack were transformed into spheres of energy before being swallowed and are released as such when the swallowed Rangers are released. However, Jason and Billy, who were swallowed whole after being caught by the monster's physical tongue, are also released as spheres of energy. This suggests that even the Rangers who are swallowed whole are transformed into energy upon entering the Terror Toad's stomach.
The Rangers that are eaten by the Terror Toad are apparently all turned into inert spheres of energy. Assuming they were conscious in this state, this must have been a nightmarish experience as they would have been trapped inside a monster's stomach, fully aware, but unable to do anything. Also, while we don't know for sure what would have become of the Rangers if Kim had not rescued them, it's very possible they would have been digested alive.
Further still, the Terror Toad claims his power grows whenever he swallows one of the Rangers, implying that he is absorbing their power. In which case, not only are the consumed Rangers steadily being absorbed by the monster, but their own power is being used to harm their friends so that the Terror Toad may eventually inflict the same fate upon them.
