In addition to dealing damage, Thunder Cage inflicts 1/8 of the target's maximum HP as damage per turn for four to five turns upon use. It also traps the target, preventing switching and escape. If the user switches out, the target will be freed.
If the user of Thunder Cage is holding a Grip Claw, the duration will always be 7 turns. If a Binding Band is held by the user, the damage done at the end of each turn will increase from 1/8 of the target's maximum HP to 1/6.