Befoul Flesh

You imbue the flesh of a willing creature you touch with necromantic energy. For the duration, the target's creature type counts as undead, if it doesn't already (in addition to any other creature type it possesses). If the target is already undead, it also gains 5 temporary hit points which lasts for the spell's duration. Additionally, an affected creature has the following features until the spell ends:

• It is resistant to necrotic and poison damage.
• It has advantage on saving throws against being poisoned or sickened.
• A creature that touches it must succeed on a Constitution saving throw or become Sickened until the end of its next turn.
• It gains no benefit from magical healing, except healing intended for undead creatures.

A Sickened creature cannot roll ability checks or attack rolls.