Devil's Pact

When a willing creature or creatures wish to make a deal, you create a binding contract...or at least an impression of one. 

From a chosen point of origin, within the range of the spell, a force of magic pulses and a visible connection (in the form of shackles, string, energy beams, etc.) forms between you and all parties engaging in the pact.

As a part of the spell, roll an Intimidation check. If the Intimidation check passes the target's passive Perception DC, the target has a feeling of significance towards this contract, and a feeling of ill-omens to come if one should break the pact.

However, that is all there is to it. Just a feeling.

When expending a spell slot:

This cantrip can be cast by expending a spell slot. If cast in this way it gains 2 new effects:
- It can only be cast on a single target, and the range is touch (requires a form of handshake).
- Breaking of this pact in any way will cause the one to break it (the caster or the target) to suffer psychic damage equal to 2d8 * level of spell + spellcasting ability modifier, and the one who got betrayed to immediately know that the pact has been broken.

The amount of creatures affected by these additional effects can never be more than your spellcasting ability modifier.

If you try to cast it on a target, that would exceed the allowed limit, you instantly suffer psychic damage equal to your spellcasting modifier * your level (not of the spell's). You then choose which deal to abandon (cannot abandon ones where the target fulfilled their part), and the new pact will take effect.

As soon as the target has fulfilled their end of the pact, and the caster theirs, the spell ends on them (and they both know it).