Beat the Bell Beast in Minutes — Where to Find It, How to Free It with the Silkspear, and Unlock Fast Travel

The Bell Beast in Hollow Knight: Silksong is an early-game boss that you’ll likely meet soon after the Moss Mother. It’s a big, jumping colossus that sits tangled in silky strings until you free it with the Silkspear. Beat it once and you unlock local fast travel — so it’s worth learning its tells and coming prepared.
Where to find the Bell Beast in Hollow Knight: Silksong
The Bell Beast lives in the northwestern part of The Marrow, just above Shakra’s first vendor spot. You probably won’t have a map until you’re close, so here’s a practical route from the start of the game.
First, get from Moss Grotto to Bone Bottom, then head east into The Marrow. When you reach a large open area with platforms (including disappearing ones), jump up and go left. Keep left until you find Shakra, the singing bug who sells maps. From there, jump to the slightly higher platform on her left and go upward. 
To free the Bell Beast you need the Silkspear. Move left from the boss area, climb across platforms to a higher section, then go right, up, and left until you reach a large nail-like structure. Inspect it to get the Silkspear. 
After grabbing the Silkspear, drop one level down and head right to find a bench if you want to save first. Return to the boss room, use the Silkspear to cut the strings, and be ready — the Bell Beast attacks immediately. 
Bell Beast’s moveset
The Bell Beast relies on a small set of powerful, telegraphed attacks. Learn the tells and you can avoid most damage reliably.
Moving underground
The boss will sink underground and then burst up. You’ll see the ground tremble right before it emerges. So, when the floor shakes, move away to avoid being hit.
Sprinting left or right
At times it will charge across the arena to trample you. Jump over it by timing a hop in the opposite direction, or back off to bait a missed sprint.
Jumping attack
When the Bell Beast roars and jumps, it crosses the room. This is actually a good opening: try running under it and slash upwards to hit its belly. The roar is the clear cue that a jump is coming.
Throwing two bells
Later in the fight the boss will pop up and toss two bells upward before disappearing. If you stay clear of the trembling ground, you’ll have time to jump past the bells.
Summoning falling bells
After you’ve damaged it a few times, the Bell Beast may vanish, reappear while yelling (a loud cue), and then make the ceiling rain dust. Bells fall from those dust streams, so avoid the dust and find safe ground quickly. 
How to prepare for the Bell Beast boss fight
Before the fight, rest at the bench located a short detour from the boss room. That gives you full health and a place to respawn nearby.
Note that cutting the strings is mandatory the first time, but if you die you won’t need to do it again. Instead, farm a few small enemies to build up Silk so you can heal or use the Silkspear offensively on re-entry.
Also consider doing the “Berry Picking” side quest for the Druid’s Eye. It’s given by the Moss Druid in the northeastern corner of Mosshome (above the Bell Beast). With the Druid’s Eye equipped, you gain a bit of Silk when you take damage, which helps with survivability.
Bell Beast rewards
Beating the Bell Beast unlocks a nearby Bell Station that enables fast travel between Bone Bottom and The Marrow. Right after the fight you’ll be moved to a new area; climb the platforms and exit back to the boss arena to find the station on the right.
Interact with the Bell Station to fast travel. As you progress, more stations will appear across the map, expanding your options.