If Midfirst gets a lien on Wacondo then that means they'll have a legal claim to it, which means that if Phil ever sells the place, or more realistically if his property is seized and sold by someone else (like the IRS for not paying backtaxes for example), then Midfirst gets their money from that sale first, and then Phil will receive whatever's leftover if any money remains. Needless to say this is a very bad thing for Phil since they're effectively getting money that would've been his otherwise.