Hey! Do You Have Tips On How To Make A Low Cr Monster More Challenging? I Have A Cool Idea For A Dungeon/boss

Hey! Do you have tips on how to make a low cr monster more challenging? I have a cool idea for a dungeon/boss but the only monster that fits is way too easy for my players. Thanks!

Oh, absolutely!

-Other targets. Make there other targets in the battle, even if they aren’t stereotypical minions. The players could have to destroy traps like swinging axes, they could have to accomplish certain checks and objectives while the battle is going on, etc

-Items and abilities. Give the boss some better weapons, even if it’s just trading out a light crossbow for a heavy one. You could also give them some sort of magic weapons, armor, or items. If you don’t want to give items the players can take, maybe add a feat or something to make the battle more interesting. Or just straight up steal other monster abilities, when it makes sense. Maybe the basilisk boss lives in a swamp and CAN breath underwater. You can mess around with statblocks!

-Speaking of statblocks… You can change around some stats. A leader of a group might have higher charisma and intelligence than the typical statblock for its monster type would warrant.

-Terrain!! You can gain so much of an advantage by messing with terrain. You can obscure areas with dust, foliage, cobwebs, rain, and so on to give the attackers an ambush opportunity or places to hide. Pitfalls, uneven terrain like ice and steep rock, or areas that need to be navigated by more than just movement (checks to swim in a rapids, climb a wall, etc) can call for interesting strategy- especially when it manages to separate the party (not fully split, just make party members less accessible to one another).