Conjure Trap

2nd-level Conjuration
Casting Time: 1 action
Range: Touch
Components: VS
Duration: (C) 24 hours

You touch the ground and conjure a magical trap with a floating red or blue crystal in the middle. Once placed, the trap remains until either the spell expires or a non-ally creature comes within 10 feet of the trap. The caster may attempt to hide the trap by making a Stealth check, which usually takes about 5 minutes of effort. Choose one of the four following effects for the trap.
Explosive. Once triggered, the trap explodes with violent force. Those within 20 feet must make a Dexterity saving throw or take 4d8 points of fire damage, or half as much damage on a successful one.
Freezing. The trap targets the first creature that comes within range. That creature must succeed on a Constitution save or take 3d8 cold damage, or half as much damage on a successful one. A creature who fails this save gains is frozen for 1 minute or until it takes damage.
Frost. Once triggered, the trap covers the ground within a 30-foot radius with slick frost. Those walking faster than half their speed through the area must succeed on a Dexterity saving throw or be knocked prone, taking 1d8 bludgeoning damage from the fall. Targets that have used the Dash action have disadvantage on their roll. The frost lasts for 5 minutes.
Immolation. Once triggered, the trap explodes into a wash of fire. Everyone within 20 feet of the trap must make a Dexterity saving throw or take 2d8 fire damage and be set on fire. A successful save halves the damage and avoids being set on fire.
At Higher Levels. When you cast this spell at 3rd level or higher, the damage of all of these effects increases by 1d8 for each spell level above 2nd.

Source: Homebrew