I have found what may be the springcord, but it's sure not a boxing glove...

That's a screenshot from 1.00g. It doesn't work in 1.10 or higher, probably works in 1.00h, though I don't have that version for testing. To view it yourself, place byte 224/E0 at address 520148/7EFD4 in TRAINER.LEV and it'll be a bit to the right of the starting position. Or you could place it elsewhere in some oher level, of course, that's just arbitrary. The next three bytes represent its parameters if you want to try to fool with those. Enjoy!

(Pyro suggests as an alternate location 934a0 in CASTLE1.LEV)

EDIT: Just as some initial information:
* The springcord is not solid and does not affect Jazz in any way.
* If only one springcord is present, the cord stretches from the event to the midpoint between the event and Player 1.
* If more than one springcord is present, the last bomb is in the midpoint position, but all cords share the same bend.
* Weapons can hit the springcord event, though not the cord itself.
* Ice causes the springcord to permanently disappear.
* TNT has no effect.
* Fireballs (Gun8) pass right through the event with no effect.
* Apparently springcord is a word in Dutch... it means bungee cord or jumprope or something.