"Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it)"
This is the Devour ability, the main mechanic of the Jund shard. This example is taken from Tar Fiend. Other Devour abilities vary in size, some are Devour 1 (coming into play with that many counters), some Devour 2 and some are even Devour 3. Many Devour creatures have an additional ability which depends on how many creatures they Devoured. For example, Tar Fiend again says "When Tar Fiend enters the battlefield, target player discards a card for each card it devoured."