Worldspine Wurm

Trample
When Worldspine Wurm dies, create three 5/5 green Wurm creature tokens with trample.
When Worldspine Wurm is put into a graveyard from anywhere, shuffle it into its owner's library.

Duskmourn: House of Horror Commander

The List

Secret Lair Drop

Explorer Anthology 3

Return to Ravnica

Trample
When Worldspine Wurm dies, put three 5/5 green Wurm creature tokens with trample onto the battlefield.
When Worldspine Wurm is put into a graveyard from anywhere, shuffle it into its owner's library.

Worldspine Wurm's last ability is a triggered ability, not a replacement ability. Players can respond to this ability, for example, by trying to exile Worldspine Wurm from the graveyard before it's shuffled into a library.