Harold and Bob, First Numens

a Treefolk attacks — 165 cards in the game can cause this (Harold and Bob is one).

1. Fangorn, Tree Shepherd — When Harold and Bob, First Numens attacks, Fangorn, Tree Shepherd adds that much mana

a Treefolk creature enters the battlefield — 172 cards in the game can cause this (Harold and Bob is one).

1. Orchard Warden — When Harold and Bob, First Numens enters, Orchard Warden gains you that creature's toughness life

a Treefolk enters the battlefield — 174 cards in the game can cause this (Harold and Bob is one).

1. Quickbeam, Upstart Ent — When Harold and Bob, First Numens enters, Quickbeam, Upstart Ent gives +2/+2

a Mutant attacks — 280 cards in the game can cause this (Harold and Bob is one).

1. Wolverine, Claws Out — When Harold and Bob, First Numens attacks, Wolverine, Claws Out makes your creatures bigger

a Mutant deals combat damage — 280 cards in the game can cause this (Harold and Bob is one).

1. Heroes in a Half Shell — When Harold and Bob, First Numens deals combat damage, Heroes in a Half Shell puts a counter on a permanent

a Mutant enters the battlefield — 286 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens enters:

1. Genghis Frog — makes a token
2. X-23, Deadly Weapon — puts a counter on a permanent
3. April O'Neil, Live on the Scene — triggers

anything leaves a graveyard — 2,503 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens leaves a graveyard:

1. Blastoneuron — makes each opponent lose 1 life
2. Defiled Crypt // Cadaver Lab — makes a token
3. Teval, the Balanced Scale — makes a token
4. Hologram Stalker — makes a token
5. Tormod, the Desecrator — makes a token
6. Quintorius, Field Historian — makes a token
7. Garrison Excavator — makes a token
8. Amzu, Swarm's Hunger — makes a token
9. Kirol, History Buff // Pack a Punch — becomes prepared
10. Teval's Judgment — triggers

13 other cards care about it too. These are the ones with the most connections.

anything attacks — 17,934 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens attacks:

1. Far Fortune, End Boss — deals 1 damage
2. Temmet, Naktamun's Will — draws you 1 card
3. Grim Javelineer — gives +1/+0
4. Invisible Woman — triggers
5. Caesar, Legion's Emperor — sacrifices a creature
6. Guide of Souls — triggers
7. Campsite Cuisine — sacrifices a Food
8. Gossip's Talent — triggers
9. Banon, the Returners' Leader — draws and discards
10. Toph, Earthbending Master — puts a counter on a permanent

112 other cards care about it too. These are the ones with the most connections.

a creature attacks — 17,934 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens attacks:

1. Adaptive Omnitool — searches a library
2. Anthem of Rakdos — gives +2/+0
3. Kindred Discovery — draws you 1 card
4. Invasion of New Capenna // Holy Frazzle-Cannon — puts counters on a permanent
5. Chorale of the Void — brings a card back
6. Saw — sacrifices a creature
7. Gisa's Favorite Shovel — makes an opponent sacrifice a creature
8. Ultima Weapon — kills a creature an opponent controls
9. Path of Mettle // Metzali, Tower of Triumph — triggers
10. Total War — kills a creature

180 other cards care about it too. These are the ones with the most connections.

a creature blocks — 17,934 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens blocks:

1. Mage Hunters' Onslaught — makes a player lose 1 life
2. Tide of War — sacrifices a creature
3. Dead-Iron Sledge — kills a creature
4. Dwindle — kills a creature

24 other cards care about it too. These are the ones with the most connections.

a nontoken creature attacks — 17,934 cards in the game can cause this (Harold and Bob is one).

1. Mardu Ascendancy — When Harold and Bob, First Numens attacks, Mardu Ascendancy makes a token

2 other cards care about it too. These are the ones with the most connections.

a creature enters the battlefield — 19,800 cards in the game can cause this (Harold and Bob is one).

When Harold and Bob, First Numens enters:

1. Slash, Reptile Rampager — deals 2 damage
2. Gimli of the Glittering Caves — puts counters on a permanent
3. Ray Fillet, Wave Warrior — puts a counter on itself
4. Legolas Greenleaf — puts a counter on a permanent
5. The Neutrinos — gets +1/+0
6. Wingnut, Bat on the Belfry — grants flying, haste and menace
7. Aetherstorm Roc — puts a counter on a permanent you control
8. Raphael, Most Attitude — exiles a card from your library

300 other cards care about it too. These are the ones with the most connections.

anything enters the battlefield — 26,499 cards in the game can cause this (Harold and Bob is one).

1. Prowl, Stoic Strategist // Prowl, Pursuit Vehicle — When Harold and Bob, First Numens enters, Prowl, Stoic Strategist // Prowl, Pursuit Vehicle puts a +1/+1 counter on itself
2. Ivora, Insatiable Heir — When Ivora, Insatiable Heir enters thanks to Harold and Bob, First Numens, it makes a token
3. Dogmeat, Ever Loyal — When Dogmeat, Ever Loyal enters thanks to Harold and Bob, First Numens, it mills a card
4. The Earth King — When The Earth King enters thanks to Harold and Bob, First Numens, it makes a token
5. SP//dr, Piloted by Peni — When SP//dr, Piloted by Peni enters thanks to Harold and Bob, First Numens, it puts a counter on a creature
6. Mu Yanling, Wind Rider — When Mu Yanling, Wind Rider enters thanks to Harold and Bob, First Numens, it makes a token
7. The Rani — When The Rani enters thanks to Harold and Bob, First Numens, it makes a token
8. J. Jonah Jameson — When J. Jonah Jameson enters thanks to Harold and Bob, First Numens, it triggers
9. Ultimecia, Temporal Threat — When Ultimecia, Temporal Threat enters thanks to Harold and Bob, First Numens, it taps a creature an opponent controls

31 other cards care about it too. These are the ones with the most connections.