Spike Growth Damage Macro?

Anyone able to help with a macro for me to quickly work out damage for this when multiple enemies walk through difference distances? I am thinking like a drop down box option with 5,10,15,20,25,30,35 and 40ft selectable options that roll 2d4 for each 5 ft?

Simplest would be this: &{template:default} {{name=Spike Growth}} {{Damage=[[ [[floor(?{Distance traveled?|5}/5)*2]]d4]] damage over ?{Distance traveled?}ft.}} and just run it once per enemy, you can change the default after the pipe | to whatever is most common. You can use a @{target|token_name} if you're a player, or a @{selected|token_name} call if you're DM and want to output who is taking  what damage. If this is 5e it would look better in a 5e template so it matches other damage output, but the math is the same.

Works perfectly, thank you so much Oosh.

No problem! I've always wanted to roll a grappling specialist with absurd movement speed to facedrag something obscenely nasty in circles around spike growth! I think the theorycrafted maximum speed is around 5000ft per turn, halved for the grapple would be 2500 feet or 1000d4 damage. Take that, quantum roll server!