You also interact profitably with stun counters and -1/-1 counters
Its second-best feature is to double the triggers from the doctors abilities, so The Tenth Doctor can get plenty of Allons-y triggers, while The Ninth Doctor can get an extra upkeep, and so on
This capability on a small, +1/+1 counter-growing corgi package is a lovable one
Some flick their cards, or bend them in their hand without even noticing
The concept art comes from illustrator Vincent Proce, and is just a part of a much bigger piece, which depicts Ulamog in its early tentacle glory
The activating player reveals the card from their hand as part of the activation cost, and the card remains revealed until it either leaves their hand or until the end of that upkeep step