You may be the only one. Its compeletly useless in my opinion, because its a puddle but it doesnt work like a puddle. But erron Black can throw spikes and not only does it do damage overtime, even while they're laying there..it slows their movement. He can get hella damage off that just by throwing them on the ground, grabbing you...and stabbing you with the sword. Reptile, would be only able to really get max damage off it, if their laying there, and u throw them down in off of his f21 grab. but even that doesnt work. Its trash
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They actually both function the same way. The only difference is the fact that caltrops stops you from running.
You may think they are different because of each individual characters tool set. The reason caltrops do damage while you're grounded is because erron blacks throw and command grab both keep your hitbox active so the caltrops do damage. Otherwise when you lay grounded you are invulnerable to caltrops just as you are to puddle.
Unfortunately reptile does not have any moves that keep your hitbox active while you are laying flat so it seems like the move is working incorrectly. His throw picks you up and over the hit box so throws dont absorb puddle damage.
Corner combos off of back 2 keep characters low enough to the point where they will proc the puddle damage while being combod.
One buff that would fix this issue would just be to simply raise the vertical hitbox of the puddle, that way it would still tick during throw even though reptile lifts you off the ground.
Otherwise the puddle works as intended, we have to think about the overall toolset the character has. If the puddle is buffed to impair movement then nimble would become too strong. When basilisk is activated there would be multiple debuffs activated.
Although that is just an example, these are the things that are brought up during development of certain movesets.
The move is pretty strong as it is i would just fix the hitboxes a bit.