Identifying Climbing Onion (Bowiea) vs. Pencil Cactus (Euphorbia)

A "weird plant" with a bulbous base is likely Climbing Onion (Bowiea volubilis); if no bulb, it's Pencil Cactus (Euphorbia tirucalli). Both need cactus care.

Climbing Onion (Sea Onion)

• Large above-ground bulb (onion-like).
• Twining green stems.
• Dormant in summer; grows in winter.
• Sandy soil, bright light, water only when dry for days.

Pencil Cactus (Milkbush)

• No bulb; slender green cylindrical stems.
• White latex sap (toxic, irritant).
• Same cactus care: sandy soil, full sun, minimal water.

Resources

• Bowiea care
• Dave's Garden Bowiea
• Pencil Cactus
• Denver Plants Euphorbia

Treat like a cactus either way. Wear gloves if it's Euphorbia.