From Worms Knowledge Base
When a team dies with Donor Card activated in the scheme settings, its last worm will spawn a Donor Card instead of the grave normally created. The Donor Card contains all the super weapons and utilities the team had in its stock, whether they were collected during the game or there to start with. It does not contain any regular weapons.
The items picked up from a Donor Card are announced sequentially at the top of the screen, with the super weapons first in a seemingly random order and then the utilities in the order they appear in the weapon selection menu. If a Donor Card contains a lot of different items, the announcements list only the first 19 of them.
If the scheme has infinite ammo for an utility or a super weapon item, the pick up announcement will read -1x item name for that item. This has no effect.